Clinical laboratory diagnostics of the Russian Federation. Methods of clinical laboratory diagnostics Types of laboratory examinations by type of biomaterial under study
Federal State Educational Institution
secondary vocational education
Krasnoyarsk Medical and Pharmaceutical College
Federal Agency for Health and Social Development"
N.V.Vlasova
Methods
clinical laboratory research
in the field of secondary medical education as a teaching aid for students of secondary medical educational institutions,
students in the specialty 060110 "Laboratory diagnostics"
Krasnoyarsk
Reviewer: D.A. Grishchenko, chief specialist in clinical and laboratory
Diagnosis of the Health and Drug Agency
Provisions for the Administration of the Krasnoyarsk Territory, Head
Clinical diagnostic laboratory of the Krasnoyarsk regional
Hospitals No. 1.
Vlasova N.V.
B 58 Methods of clinical laboratory research: Educational
Benefit. / N.V. Vlasov. – Krasnoyarsk: Krasnoyarsk medical
College of Pharmacy, 2008.- 222p.
This manual is a systematic material on the methods of clinical laboratory research.
Consists of two sections. The first section contains information on the methods of obtaining and laboratory testing of urine, gastric juice, bile, feces, cerebrospinal fluid, sputum, genital secretions, fluids of serous cavities, as well as the results of these studies in the norm and the nature of their changes in diseases. The second section of the manual is devoted to hematological studies.
Designed for students of secondary specialized educational institutions studying in the specialty "Laboratory Diagnostics".
List of abbreviations …………………………………………………………………………….9
Foreword ………………………………………………………………………………………10
Introduction ………………………………………………………………………………………..11
^ Section I. GENERAL CLINICAL STUDIES ….......................13
Chapter 1. Urinalysis………………………………………………………………..13
Formation and composition of urine …………………………………………………………...13
Urine examination …………………………………………………………………….14
1.2.1.1. Amount of urine ………………………………………………………………..15
1.2.1.2. Urine color …………………………………………………………………………..15
1.2.1.3. Urine transparency ……………………………………………………………...16
1.2.1.4. Urine reaction ……………………………………………………………………….17
1.2.1.5. The smell of urine ………………………………………………………………………….18
1.2.1.6. Relative density of urine ………………………………………………...18
1.2.1.7. Zimnitsky test ……………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………
1.2.1.8. Control questions on the topic "Research of physical
Properties of urine "…………………………………………………………………...20
1.2.2. Chemical examination of urine …… ………………………………………………..20
1.2.2.1. Determination of protein in urine ……………………………………………………...20
1.2.2.2. Determination of glucose in urine …………………………………………………..25
1.2.2.3. Determination of ketone bodies in urine ……………………………………………27
1.2.2.4. Determination of urobilin and bilirubin in urine ………………………………..28
1.2.2.5. Determination of blood pigment in urine ………………………………………..30
1.2.2.6. Control questions on the topic "Chemical examination of urine" ………...31
1.2.3. Microscopic examination of urine sediment ……………………………………..31
1.2.3.1. Approximate method ………………………………………………………..31
1.2.3.2. Quantitative methods ………………………………………………………..36
1.2.3.3. Control questions on the topic "Microscopic examination
Urine Sediment” ………………………………………………………………………38
1.2.4. Urine examination using test strips ………………………………………………………………………………………………………………………………………………………………………………………………………………
1.3. Urinary syndromes ……………………………………………………………………...39
1.4. Final control questions for the chapter "Urine examination" ………………41
Chapter 2 Examination of gastric secretion ……………………………………………44
2.1. Functions of the stomach. Composition of gastric juice ……………………………………………..44
2.2. Methods for studying gastric secretion …………………………………………...45
2.2.1. Phases of gastric secretion ……………………………………………………………..45
2.2.2. Fractional method of gastric sounding …………………………………………..46
2.2.3. Control questions on the topic "Methods for the study of gastric
Secretions” ………………………………………………………………………………47
2.3. Examination of gastric juice ………………………………………………………..47
2.3.1. Physical properties ……………………………………………………………………48
2.3.2. Chemical research …………………………………………………………...48
2.3.2.1. Determination of acidity …………………………………………………………48
2.3.2.2. Determination of the production rate of hydrochloric acid ………………………………………...50
2.3.2.3. Determination of hydrochloric acid deficiency ………………………………………..50
2.3.2.4. Determination of lactic acid ………………………………………………….51
2.3.2.5. Determination of proteolytic activity ………………………………….51
2.3.2.6. Intragastric pH-metry ……………………………………………………52
2.3.3. Microscopic examination of gastric contents ……………………52
2.3.4. Control questions on the topic "Study of gastric juice" ……………… 53
2.4. Tubeless methods for assessing the acidity of gastric juice ………………………… 53
2.5. Final control questions for the chapter "Research
Gastric secretion "………………………………………………………………………………………………………………………………………54
Chapter 3 Examination of duodenal contents ……………………………………..56
3.1. Composition and functions of bile. Physiology of the formation and secretion of bile ……………..56
3.2. Methods of duodenal sounding ……………………………………………………..57
3.3. Examination of duodenal contents …………………………………………….59
3.3.1. General properties ………………………………………………………………………….59
3.3.2. Microscopic examination ……………………………………………………60
3.4. Diagnostic value of duodenal sounding ……………………………...62
3.5. Control questions for the chapter "Research of duodenal contents" ……….63
Chapter 4 Examination of feces …………………………………………………………………64
4.1. Composition of feces ………………………………………………………………………………..64
4.2. Examination of feces ………………………………………………………………………...64
4.2.1. General properties of feces …………………………………………………………………….64
4.2.2. Chemical examination of feces …………………………………………………………67
4.2.3. Control questions on the topic “Physical and chemical properties of feces” …………….68
4.2.4. Microscopic examination of feces ……………………………………………...69
4.2.4.1. Microscopic elements of feces ……………………………………………….69
4.2.4.2. Remains of protein food in the feces ………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………
4.2.4.3. Residues of carbohydrate food in feces ……………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………….
4.2.4.4. Remaining fats in the feces ……………………………………………………………..72
4.2.4.5. Cellular elements of feces …………………………………………………………73
4.2.4.6. Crystal formations …………………………………………………….73
4.2.4.7. Microflora ………………………………………………………………………..73
4.2.4.8. Control questions on the topic "Microscopic examination of feces" ... 75
4.3. Coprological syndromes ……………………………………………………………...75
4.4. Final control questions for the chapter “Stool Examination” ……………….77
Chapter 5 Study of cerebrospinal fluid …………………………………..78
5.1. Education, functions and obtaining liquor ……………………………………………...78
5.2. The study of cerebrospinal fluid ……………………………………………………………………….79
5.2.1. Physical properties of liquor …………………………………………………………..79
5.2.2. Microscopic examination of cerebrospinal fluid ………………………………………….80
5.2.3. Chemical study of cerebrospinal fluid ………………………………………………….82
5.3. Characteristics of cerebrospinal fluid in certain diseases of the central nervous system ………………………….84
5.4. Control questions for the chapter "Investigation of cerebrospinal fluid" ...... ... 86
Chapter 6 Study of exudates and transudates……………………………………….87
6.1. Types of punctates …………………………………………………………………………….87
6.2. Examination of fluids of serous cavities …………………………………………...88
6.2.1. Determination of physico-chemical properties ……………………………………………89
6.2.2. Microscopic examination …………………………………………………...89
6.3. Control questions for the chapter "Examination of exudates and transudates" ………...91
Chapter 7. Sputum examination …………………………………………………………….91
7.1. Sputum collection ……………………………………………………………………………..92
7.2. Safety rules for working with sputum …………………………………..93
7.3. Sputum examination …………………………………………………………………………94
7.3.1. Determination of the general properties and nature of sputum …………………………………...94
7.3.2. Control questions on the topic “General properties of sputum” ……………………… 97
7.3.3. Microscopic examination of sputum ……………………………………………97
7.3.3.1. Preparation and study of native sputum preparations ………………….97
7.3.3.2. Cellular elements of sputum ……………………………………………………98
7.3.3.3. Fibrous formations in sputum ………………………………………….99
7.3.3.4. Crystalline formations of sputum … ………………………………….100
7.3.4. Bacterioscopic examination of sputum ……………………………………….101
7.3.4.1. Preparation and fixation of smears …………………………………………...101
7.3.4.2. Ziehl-Nielsen staining ……………………………………………….102
7.3.5. Control questions on the topic "Microscopic and
Bacterioscopic examination of sputum "…………………………………….104
7.4. Characteristics of sputum in certain diseases of the respiratory system ...... .104
7.5. Final control questions for the chapter "Sputum examination" …………105
Chapter 8. Examination of the discharge of the genital organs …………………………………106
8.1. Laboratory investigations for predominantly transmitted infections
Sexually ……………………………………………………………………………..106
8.1.1. Syphilis …………………………………………………………………………………106
8.1.2. Gonorrhea ……………………………………………………………………………….109
8.1.3. Urogenital chlamydia ………………………………………………………...109
8.1.4. Urogenital trichomoniasis …………………………………………………………111
8.1.5. Bacterial vaginosis ……………………………………………………………...112
8.1.6. Urogenital candidiasis ……………………………………………………………..112
8.1.7. Control questions on the topic “Laboratory studies for STIs” …….113
8.2. Examination of the contents of the vagina ………………………………………………...114
8.2.1. Cytological studies ……………………………………………………..114
8.2.1.1. Taking material and preparing preparations for microscopy …………114
8.2.1.2. Morphology of vaginal epithelial cells ………………………………..115
8.2.1.3. Cytological assessment of vaginal smears ……………………………….116
8.2.2. Determination of the degree of purity of vaginal contents ……………………...118
8.2.3. Control questions on the topic "Examination of the contents of the vagina" ...... ... 119
8.3. Examination of ejaculate and prostate secretion …………………………...119
8.3.1. Composition and production of seminal fluid …………………………………………..120
8.3.2. Study of the ejaculate …………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………
8.3.2.1. Physical and chemical research …………………………………………...121
8.3.2.2. Microscopic examination of the ejaculate …………………………………….122
8.3.3. Examination of the secretion of the prostate gland ………………………………………………………………………………125
8.3.4. Control questions on the topic "Research of ejaculate and
Secrets of the prostate gland "…………………………………………………..126
Chapter 9 Laboratory diagnosis of mycoses …………………………………………...127
9.1. Classification of mycoses ………………………………………………………………...127
9.2. Technique for taking material and preparing preparations for
Microscopic examination ……………………………………………………..128
9.3. Laboratory diagnosis of fungal diseases of the skin …………………………...129
9.4. Rules for safe work in a mycological laboratory ………………………...131
9.5. Control questions for the chapter "Laboratory diagnosis of mycoses" ……………… 131
S e c tio n II. HEMATOLOGICAL STUDIES…………. 132
Chapter 1. General clinical blood test …………………………………………...132
Composition and functions of blood …………………………………………………………………..132
Taking blood for research ……………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………
Determination of the concentration of hemoglobin in the blood ……………………………………….135
1.3.2. Methods for determining the concentration of hemoglobin in the blood………………………..137
1.3.3. The clinical significance of blood hemoglobin …………………………………………..137
1.3.4. Control questions on the topic "Determination of concentration
Blood hemoglobin "…………………………………………………………………….138
1.4. Determination of erythrocyte sedimentation rate ……………………………………………138
1.4.1. Factors affecting ESR ………………………………………………………..138
1.4.2. Methods for determining ESR ……………………………………………………………..139
1.4.3. Clinical significance of ESR …………………………………………………………...139
1.4.4. Control questions on the topic "Determination of ESR" …………………………….140
1.5. Determination of the number of leukocytes in the blood ………………………………………...140
1.5.1. Functions of leukocytes ………………………………………………………………..140
1.5.2. Methods for counting the number of leukocytes in the blood ………………………………..141
1.5.3. The clinical significance of the number of leukocytes in the blood …………………………..142
1.5.4. Control questions on the topic "Determination of the number of leukocytes
In the blood” ………………………………………………………………………………..143
1.6. Determination of the number of red blood cells in the blood ………………………………………...143
1.6.1. Functions of erythrocytes ………………………………………………………………….144
1.6.2. Methods for counting the number of blood erythrocytes …………………………………………………………………………………………144
1.6.3. The clinical significance of the number of red blood cells ……………………………...145
1.7.1. Color indicator of blood ………………………………………………………….146
1.7.2. Control questions on the topic "Determining the quantity
Erythrocytes in the blood. Color indicator of blood "……………………………….147
1.8. Calculation of the leukocyte formula ………………………………………………………...147
1.8.1. Morphology of certain types of peripheral blood leukocytes is normal ...... 147
1.8.2. Methods for calculating the leukocyte formula ………………………………………..149
1.8.2.1. Preparation of smears …………………………………………………………… 149
1.8.2.2. Coloring strokes ………………………………………………………………...150
1.8.2.3. Technique for calculating the leukocyte formula ………………………………………………………………………………152
1.8.3. Leukocyte formula in normal and pathological conditions ………………………………..152
1.8.3.1. The leukocyte formula is normal …………………………………………….152
1.8.3.2. Changes in the morphology of leukocytes in pathology ………………………...153
1.8.3.3. Change in the number of certain types of leukocytes in pathology ...... ... 154
1.8.4. Control questions on the topic "Calculation of the leukocyte formula" …………... 155
1.9. Blood changes in certain conditions and diseases ………………………..155
1.9.1. Age features of blood …………………………………………………….155
1.9.2. Blood changes during pregnancy ………………………………………………..156
1.9.3. Hereditary anomalies of leukocyte morphology ……………………………..157
1.9.4. Blood changes in purulent-inflammatory and infectious
Diseases ………………………………………………………………………… 158
1.10. Final control questions to the chapter "General clinical
Blood test» ……………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………
Chapter 2 Automatic methods for the study of blood cells… ……………………159
Chapter 3 Diagram of hematopoiesis…………………………………………………………….163
Chapter 4 anemia……………………………………………………………………………...165
4.1. Classification of anemia …………………………………………………………………….165
4.2. Laboratory signs of anemia …………………………………………………………..167
4.2.1. Changes in the morphology of erythrocytes in anemia ………………………………..167
4.3. Anemia due to blood loss ………………………………………………………..170
4.3.1. Acute posthemorrhagic anemia ………………………………………………….170
4.3.2. Chronic posthemorrhagic anemia ………………………………………...170
4.3.3. Control questions on the topics “Laboratory signs of anemia.
Anemia due to blood loss "……………………………………………………...170
4.4. Anemia due to impaired blood formation
4.4.1. Iron deficiency anemia ……………………………………………………………………………………………………………………………………171
4.4.2. Iron-saturated anemia … ……………………………………………………….172
4.4.3. В 12 (folic)-deficiency anemia ………………………………………………….172
4.4.4. Hypo- and aplastic anemia ……………………………………………………..173
4.4.5. Control questions on the topic "Anemia due to a violation
Blood formation” …………………………………………………………………….174
4.5. Hemolytic anemia … ……………………………………………………………...174
4.5.1. Causes and signs of hemolytic anemia ……………………………………………………174
4.5.2. Classification of hemolytic anemias …………………………………………...175
4.5.3. Hemolytic disease of the newborn ………………………………………………………176
4.6. Determination of the hematocrit value …………………………………………………..177
4.7. Counting the number of reticulocytes ……………………………………………………….178
4.8. Determination of the osmotic resistance of erythrocytes ………………………………………………………179
4.9. Final control questions to the chapter "Anemia" …………………………..181
Chapter 5 Radiation sickness …………………………………………………………………...182
5.1. Acute radiation sickness …………………………………………………………………….183
5.2. Chronic radiation sickness ……………………………………………………………..185
5.3. Control questions on the topic "Radiation sickness" …………………………………...185
Chapter 6. Leukemia…………………………………………………………………………….186
6.1. Etiology, pathogenesis, classification of leukemias ………………………………………186
6.2. Acute leukemia ………………………………………………………………………….187
6.2.1. Classification of acute leukemia …………………………………………………...187
6.2.2. Clinical manifestations and blood picture in acute leukemia ………………...188
6.2.3. Cytochemical characteristics of blast cells in acute leukemia ……….190
6.2.4. Control questions on the topic "Acute leukemia" ……………………………….191
6.3. Chronic leukemia …………………………………………………………………………………………………191
6.3.1. Myeloproliferative diseases ……………………………………………...191
6.3.1.1. Chronic myeloid leukemia …………………………………………………….192
6.3.1.2. Erythremia ……………………………………………………………………… 193
6.3.1.3. Chronic monocytic leukemia ………………………………………….193
6.3.1.4. Control questions on the topic "Myeloproliferative diseases" ....194
6.3.2. Lymphoproliferative diseases ……………………………………………...194
6.3.2.1. Chronic lymphocytic leukemia …………………………………………………...195
6.3.2.2. Multiple myeloma ……………………………………………………..196
6.3.2.3. Control questions on the topic "Lymphoproliferative
Diseases»…………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………….
6.4. Final control questions for the chapter "Leukemia" ……………………..197
Chapter 7 Leukemoid reactions …………………………………………………………..198
Chapter 8 Hemorrhagic diathesis … …………………………………………………….200
8.1. Classification of hemorrhagic diathesis …………………………………………….200
8.2. Determination of the number of platelets in the blood ………………………………………..201
8.2.1. Morphology and functions of platelets ……………………………………………...201
8.2.2. Methods for determining the number of platelets ………………………………………202
8.2.3. The clinical significance of the number of blood platelets …………………………..203
8.3. Determination of bleeding time and clotting time
Capillary blood …………………………………………………………………………204
8.4. Control questions for the chapter "Hemorrhagic diathesis" …………………………205
Chapter 9. Groups and Rh-affiliation of blood ……………………………………….205
9.1. Blood groups of the AB0 system ………………………………………………………………206
9.1.2. Methods for determining the blood type ………………………………………………….207
9.2. Rh-affiliation of blood ……………………………………………………………..212
9.3. Control questions for the chapter “Blood groups and Rh-affiliation” ………….214
Chapter 10. Quality control of laboratory research …………………………...215
Sample answers to test tasks …………………………………………………….220
Bibliographic list …………………………………………………………………….221
^ List of abbreviations
ACTH - pituitary adrenocorticotropic hormone
B - basophil
in / in - intravenously
i / m - intramuscularly
WHO - World Health Organization
HDN - hemolytic disease of the newborn
DNA - deoxyribonucleic acid
duodenum - duodenum
IHD - ischemic heart disease
IS - maturation index
STIs - sexually transmitted infections
KI - karyopyknotic index
KDL - clinical diagnostic laboratory
AFB - acid-fast mycobacteria
L - lymphocyte
LB - radiation sickness
MON - monocyte
MPO - myeloperoxidase
Np / I - stab neutrophil
Ns / I - segmented neutrophil
OL - acute leukemia
ARS - acute radiation sickness
SARS - acute respiratory viral infection
s / c - subcutaneously
RNA - ribonucleic acid
SI - International System of Units of Measurement
SMS - synthetic detergent
ESR - erythrocyte sedimentation rate
FEK - photoelectric colorimeter
CLL - chronic radiation sickness
CML - chronic myelogenous leukemia
CRF - chronic renal failure
CNS - central nervous system
CPC - color indicator of blood
CSF - cerebrospinal fluid
E - eosinophil
EDTA - ethylenediaminetetraacetate
EI - eosinophilic index
Foreword
The importance of laboratory research at the present stage of development of medicine is constantly increasing.
The main contingent of employees of clinical diagnostic laboratories are laboratory assistants with secondary specialized education, which imposes special requirements on their training. The lack of a sufficient number of modern textbooks on clinical laboratory research methods for secondary specialized educational institutions in the context of a sharp expansion of the range of laboratory research and technical re-equipment of clinical diagnostic laboratories determines the need to publish a textbook on clinical laboratory diagnostics for medical laboratory technicians.
This manual includes two sections - general clinical and hematological studies, consisting of several chapters. Each chapter is devoted to the laboratory analysis of a certain type of biological material (urine, contents of the gastrointestinal tract, sputum, cerebrospinal fluid, genital secretions, effusion fluids, blood) and contains information on methods for obtaining them and unified methods of laboratory research, as well as the results of these studies in norm and the nature of their changes in diseases.
The materials of the manual are set out in accordance with the documents regulating the activities of clinical diagnostic laboratories of RF LPU. Thus, the chapter "Quality control of clinical laboratory studies" covers the modern concept of the issue in accordance with the Order of the Ministry of Health of the Russian Federation No. 45 of 02/07/2000. The topic "Sputum examination" contains the recommendations of Appendix No. 10 to the order of the Ministry of Health of Russia dated 03/21/2003. No. 109 "Instructions on unified methods of microscopic examinations for the detection of acid-fast mycobacteria in clinical diagnostic laboratories of healthcare facilities." The issues of determining the group and Rh blood affiliation are given in accordance with the Order of the Ministry of Health of the Russian Federation No. 2 of 01/09/98 "On approval of instructions for immunoserology".
At the end of each topic there are control questions, and at the end of large chapters - final questions in the form of test tasks to restore compliance with the answer standards at the end of the manual. The selected form allows a limited number of test tasks to cover a large amount of material.
The manual reflects the experience gained over many years of teaching the discipline "Methods of clinical laboratory research".
Introduction
The discipline "Methods of clinical laboratory research" studies a complex of physicochemical and biological methods used to obtain objective data on the state of the human body.
As a scientific discipline, clinical laboratory diagnostics arose at the intersection of clinical medicine, anatomy, physiology, biology, physics, chemistry and other sciences. It solves the following tasks:
Development of optimal methods for the study of biological material;
Establishing limits for fluctuations in the norm for certain groups of people (by sex, age, habitat, etc.);
Establishing the diagnostic value of individual laboratory tests.
The main task of clinical laboratory diagnostics in practical medicine is to help the attending physician in diagnosing a disease, treating patients, and implementing preventive measures.
The main objects of clinical laboratory research are the contents of vessels and cavities (blood, cerebrospinal fluid, transudates and exudates, gastric juice, bile), excretions of the human body (urine, feces, sputum, seminal fluid), as well as bone marrow, punctates of lymph nodes, etc. .
The composition and properties of human biological fluids have attracted the attention of scientists since ancient times. So, already in the treatises of ancient India and China (X-VI centuries BC) there are indications of the study of the properties of urine. The Uzbek doctor Abu Ali ibn Sina (Avicenna) in his works connects the change in the nature of human excretions (urine, feces) with certain diseases. However, these observations of ancient scientists were limited only to the description of the general properties (color, quantity, smell, etc.) of biological material. The development of laboratory diagnostics as a scientific discipline was facilitated by the invention of the microscope and colorimeter, the discovery of the structure of the cell, and other advances in natural science. The first primitive clinical and diagnostic studies associated with an attempt to apply the methods of chemical analysis in medicine date back to the 16th century - the beginning of the Renaissance.
In Russia, the first clinical diagnostic laboratory was organized by the outstanding clinician S.P. Botkin at the therapeutic department of the Military Medical Academy of St. Petersburg. D.L.Romanovsky, who proposed his own method of staining blood cells, is of great merit in the development of laboratory work, which is still used today. A significant contribution to laboratory work was made by Russian scientists V.E. Predtechensky, M.N. Kost (organized the All-Union Society of Laboratory Doctors, the journal "Laboratory Business"), etc.
Optical, ionometric, immunoenzymatic, electrophoretic, chromatographic and other types of analysis, as well as methods of "dry" chemistry, are widely used in modern clinical laboratory diagnostics. To carry out many types of laboratory research, the production of special reagent kits has been launched, which significantly improves the quality of analyzes. In many clinical diagnostic laboratories of healthcare facilities, high-tech analyzers are used to perform laboratory tests in a fully automated mode.
In all laboratories, research is carried out using unified unified methods approved by the Ministry of Health of the Russian Federation and mandatory for all CDL.
Particular attention of laboratory service specialists is paid to improving the quality of analyzes, which is ensured by the introduction of special programs using control materials into the daily practice of CDL.
S e c tio n I
^ GENERAL CLINICAL STUDIES
__________________________________________________________________
Chapter 1
URINE STUDY
FORMATION AND COMPOSITION OF URINE
Urine formation.Urine is formed in the kidneys, the main function of which is to maintain the constancy of the internal environment of the body. This function is ensured by the excretion of end products of metabolism, excess salts and water, as well as toxic and foreign substances in the urine.
The urinary organs include the kidneys [lat.ren, Greek nephros], ureters [lat.ureter], bladder [lat.cystis], urethra [lat.urethra]. Inside the kidneys is the renal pelvis[lat. pyelos] . The main functional unit of the kidneys is the nephron - a collection of tubules-tubules with vascular glomeruli.
Urine formation occurs in 3 stages.
^ Stage 1 - filtration , during which the so-called "primary" urine is formed, which differs from blood plasma only in the absence of coarse proteins, since they do not pass through the kidney filter due to the very large size of the molecules. Plasma filtration occurs in the glomeruli due to increased blood pressure in the capillaries of the renal glomerulus, which is created due to the significantly smaller diameter of the efferent arterioles compared to the afferent ones.
^ Stage 2 - reabsorption - reabsorption of water and substances dissolved in it that are necessary for the body (amino acids, fine proteins, glucose, sodium, potassium, calcium, phosphates). Reabsorption occurs in the convoluted tubules of the first and second order. During the day, an adult produces 180 liters of primary urine, of which 178-179 liters are reabsorbed and only 1.0-1.5 liters of final urine is excreted. The second stage of urine formation provides the concentration function of the kidneys, that is, the ability of the kidneys to concentrate the primary urine.
^ Stage 3 - secretion in the urine by the epithelium of the convoluted tubules of hydrogen ions, potassium, ammonia, drugs, dyes. The secretion process contributes to the removal from the body of all unnecessary substances formed as a result of metabolic processes, and ensures the final formation of urine.
^ The composition of urine is normal. Urine is a liquid of complex chemical composition, in which about 150 substances are dissolved. Most of the urine (95%) is water, 5% is solid matter, of which 3.4% is organic matter and 1.6% is inorganic matter.
The organic matter of urine is represented mainly by the end products of protein metabolism - urea, uric acid, creatinine. Urine also contains a small amount of enzymes, vitamins, pigments, hormones. About 40 g of organic substances are excreted in the urine per day. Inorganic substances in urine include salts of sodium, potassium, calcium, ammonia, etc.
^ Pathological impurities of urine - components of urine that are not normally contained in it, but appear only in diseases. Pathological impurities in urine include protein, glucose, acetone bodies, bilirubin, hemoglobin, etc. The presence of pathological impurities in the urine is indicated by special terms: proteinuria (protein in the urine), glucosuria (glucose in the urine), etc.
^ URINE STUDY
General urine analysisis a widespread type of research that allows to judge the nature and severity of the pathological process in the kidneys and urinary system.
A general urinalysis includes three types of studies.
1. Determination of the physical properties of urine: quantity, color, transparency, sediment, reaction, odor, relative density.
2. Chemical examination of urine:
Qualitative determination of protein and glucose, that is, the determination of the presence of protein and glucose;
if protein and glucose are detected, their amount is determined.
A general urinalysis is carried out in the morning, the most concentrated portion of urine.
Urine collection is usually carried out by the patient himself after a thorough toilet of the external genital organs. A clean, wide-mouthed vessel with a lid is used to collect urine. Urine collected for general analysis can be stored in a cold place for no more than 1.5-2 hours.
In addition to a general urine test, at the special request of a doctor, additional chemical studies of urine can be carried out to determine ketone bodies, urobilin, bilirubin, blood pigment - hemoglobin, etc., as well as quantitative methods for microscopic examination of urine sediment (according to Nechiporenko, Kakovsky-Addis, etc. .).
1.2.1. The study of the physical properties of urine
^ 1.2.1.1. URINE AMOUNT
In a healthy adult, the daily amount of urine isdaily diuresis [from Greek. diuresisurination] is 0.8-1.5 liters.
The volume of the morning portion of urine (usually 150-250 ml) does not give an idea of the daily diuresis. To determine the daily diuresis, it is necessary to examine daily urine (that is, urine collected within 24 hours).
Under various conditions, daily diuresis may vary. An increase in daily diuresis of more than 2 liters is called polyuria [from Greek. polys many + urina urine] . It can be physiological (in healthy people under special conditions) and pathological (in diseases). Physiological polyuria is observed with the use of a large amount of fluid and with stress. Pathological polyuria develops in chronic renal failure, pyelonephritis, resorption of edema. Severe polyuria (up to 3-4 liters) is characteristic of diabetes mellitus. Especially sharp polyuria (up to 30 liters per day) is observed in diabetes insipidus (insufficiency of the pituitary antidiuretic hormone).
Oliguria [from Greek. oligossmall amount +urina] - decrease in daily diuresis less than 0.6 liters. It can also be physiological and pathological. Physiological oliguria occurs when drinking is limited, the loss of a large amount of fluid with sweat during significant physical exertion and high ambient temperature. Pathological oliguria occurs in kidney diseases (acute renal failure, acute glomerulonephritis), as well as in extrarenal fluid loss (vomiting, diarrhea, burn disease).
Anuria [from Greek. a absence + urina] - a complete cessation of urine output is true, which depends on the cessation of urine production by the kidneys (in acute renal failure), and mechanical - due to the presence in the urinary tract of a mechanical obstacle to the outflow of urine (stones, tumors).
Daily diuresis is divided into day and night. Normally, the ratio of daytime diuresis to nighttime is 3:1 - 4:1, that is, daytime diuresis is 3-4 times greater than nighttime. The predominance of nocturnal diuresis over daytime is called nocturia [from Greek. nyx, nyktos night + urina] and is observed in chronic renal failure, prostate tumors.
Dysuria - painful urination [from the Greek.dys violation + urina] and pollakiuria – frequent urination [from Gr.pollakis frequent + urina] are characteristic of cystitis (inflammation of the bladder).
URINE COLOR
Normal urine has a straw-yellow color of varying intensity. The characteristic color of urine is given by the pigments contained in it:urochromes A and B, uroerythrin, stercobilinogen, which in urine is called urobilin . The intensity of urine color in healthy people depends on the amount of fluid drunk: with an increased drinking regimen, urine becomes lighter, and with limited drinking, increased sweating, it acquires a more intense yellow color. Some foods and drugs can make urine different colors. Red (pink) color is given to urine by amidopyrine, aspirin, beets; brown - salol and naphthol; blue-green - methylene blue; brown - activated carbon, etc. The reasons for changing the color of urine in pathology are presented in Table 1.
Table 1
Reasons for changing the color of urine
| urine color | Pathological condition | ^ Cause of color change |
| Dark yellow | Edema, vomiting, diarrhea, burn disease | High concentration of pigments |
| Pale, watery | Diabetes, diabetes insipidus | Low concentration of pigments |
| Red | Kidney disease (renal colic) | Hematuria (unaltered blood) |
| "Meat slops" | acute glomerulonephritis, cystitis | Hematuria (changed blood) |
| "Strong tea" | Hemolytic jaundice | Urobilinuria |
| "Beer" | Parenchymal jaundice | Bilirubinuria + urobilinuria |
| "Beer" | Mechanical jaundice | Bilirubinuria |
| Black | Hemolytic kidney | Hemoglobinuria |
| Whitish | Fatty degeneration of the kidneys | Drops of fat |
^ 1.2.1.3. CLARITY OF URINE
Normally, freshly excreted urine is clear. When standing, it becomes cloudy due to the precipitation of salts and cellular elements, the multiplication of bacteria.
table 2
Causes of cloudy urine and how to remove it
| ^ Cause of cloudy urine | Haze Removal Methods |
| Cellular elements: erythrocytes, leukocytes, epithelium | |
| Slime | Centrifugation, filtration |
| Fat | Adding ether |
| bacteria | bacteria filter |
| urats | Heating, adding alkali |
| Phosphates | Addition of acetic acid |
| Oxalates | Adding hydrochloric acid |
In diseases, cloudy urine may be excreted. In these cases, turbidity may be due to a large number of cellular elements (erythrocytes, leukocytes), bacteria, fat, salts.
The transparency of urine is assessed by eye as: transparent, cloudy, cloudy.
^ Urine sedimentformed during prolonged standing or when urine is cooled to 0 ° C. Precipitation may consist of salts and cellular elements.
Macroscopically (that is, by eye), precipitation is described according to three criteria:
color (white, pink, brick red, etc.);
character (amorphous, crystalline);
expressiveness (abundant, insignificant).
^ 1.2.1. 4. URINE REACTION
Normally, the reaction of urine is slightly acidic or neutral (pH = 5.0-7.0). In healthy people, the reaction of urine depends mainly on the food taken. From the use of meat food, it shifts to the acid side, and from plant foods - to the alkaline.
Table 3
Reasons for changing the reaction of urine
^ Methods for determining the reaction of urine
With the help of indicator paper (universal indicator paper with a pH range of 1.0-10.0; special indicator paper for determining the pH of urine with a range of 5.0-8.0, combined test strips).
A unified method with a liquid indicator bromthymol blue (pH determination range 6.0-7.6) according to Andreev.
Determination of urine reaction with bromthymol blue indicator (according to Andreev)
Reagent: 0.1% solution of bromthymol blue indicator.
^ Research progress. To 2-3 ml of urine add 1-2 drops of the indicator. The urine reaction is judged by the color of the solution: yellow color corresponds to an acid reaction, brown color - slightly acidic, grassy color - neutral reaction, brown-green color - slightly alkaline reaction, blue-green color - alkaline reaction.
This test is very simple, but gives only an approximate idea of the reaction of urine. It is impossible to distinguish urine with normal pH from pathologically acidic by this method.
^ 1.2.1.5. SMELL OF URINE
It has no significant diagnostic value. Normally, urine has a mild specific odor.
With prolonged storage, accompanied by bacterial decomposition, urine acquires a sharp ammonia smell. The same smell has urine with cystitis. In diabetes mellitus, the urine smells of acetone (rotten fruit) due to the presence of acetone bodies in it.
^ 1.2.1.6. RELATIVE DENSITY OF URINE
The relative density (specific gravity) of urine is proportional to the concentration of substances dissolved in it: urea, uric acid, creatinine, salts.
In healthy people, the relative density of urine fluctuates during the day from 1.005 to 1.030. In the morning, the most concentrated portion of urine, it is 1.020-1.026.
The presence of pathological impurities in it - protein and glucose - affects the relative density of urine. Every 3g/l of protein increases the relative density of urine by 1 division of the urometer (0.001), and every 10g/l of glucose by 4 divisions (0.004).
A low relative density of urine occurs with polyuria and chronic renal failure, and a very high one - up to 1.040-1.050 - most often with diabetes mellitus.
The relative density of urine gives an idea of the concentrating capacity of the kidneys, that is, the ability of the renal tubules to concentrate primary urine by reabsorbing water from it. The value of the relative density of the morning portion of urine, equal to or greater than 1.018-1.020, indicates the preserved concentration function of the kidneys.
The relative density of urine is determined using a urometer - a special hydrometer with a scale of 1.000 to 1.050.
^ 1.2.1.7. ZIMNITSKY TEST
It is one of the methods for studying the functional state of the kidneys, it is used to assess the concentration ability of the kidneys. The test consists in dynamic monitoring of the amount and relative density of urine in 3-hour portions during the day. A prerequisite for the test is the usual drinking regimen, especially the exclusion of excessive fluid intake.
On the eve of the study, 8 cans are prepared. Mark them, indicating the name of the subject and the time of urine collection:
6-9 o'clock 5. 18-21 hours.
9-12 o'clock. 6. 21-24 hours.
12-15 hours. 7. 0-3 hours.
15-18 hours. 8. 3-6 hours.
At 6 o'clock in the morning, the subject empties the bladder, but this portion of urine is not used for analysis. Then, every 3 hours during the day, the patient collects urine in jars with the appropriate time designation.
In the laboratory, in all 8 portions, the relative density and the exact amount of urine are determined using a measuring cylinder.
To evaluate the Zimnitsky test, you must:
Calculate separately daytime and nighttime diuresis. Daytime diuresis is determined by summing up the amount of urine in the first 4 portions, and nighttime diuresis - in the last four;
Determine the maximum and minimum relative density during the day and determine the difference between them (max ρ - min ρ).
The results of the Zimnitsky test are normal. The normal concentration function of the kidneys is characterized by: the ratio of daytime diuresis to nighttime 3:1 - 4:1; the difference between the maximum and minimum relative density is equal to or greater than 0.016.
A change in the ratio between daytime and nighttime diuresis, nocturia, a decrease in the difference between the maximum and minimum relative density of urine, as well as isostenuria and hypostenuria, indicate a violation of the concentration ability of the kidneys.
Isosthenuria [from Greek. isos equal + urina] - urine excretion during the day (in all 8 portions) with a constant relative density equal to the relative density of blood plasma - 1.010-1.011. Isosthenuria indicates a complete loss of concentrating ability by the kidneys and is characteristic of chronic renal failure.
Hypostenuria [from Greek. hypo below normal + urina] – urine excretion during the day (in all 8 portions) with a constant relative density less than the relative density of blood plasma, that is, less than 1.010. Hypostenuria indicates a sharp violation of the concentration function of the kidneys.
^ 1.2.1.8. CONTROL QUESTIONS ON THE TOPIC "RESEARCH OF THE PHYSICAL PROPERTIES OF URINE"
1. What studies are included in the general analysis of urine?
2. How does daily diuresis change at high ambient temperature?
3. What disease is characterized by pronounced polyuria?
4. What is hypostenuria?
5. What determines the value of the relative density of urine?
6. How is the relative density of urine determined?
7. What substances significantly increase the relative density of urine?
8. What is the true relative density of urine with a urometer reading of 1.038 and a glucose content of 15 g/l?
9. What is the principle of the Zimnitsky test?
10. What stage of urine formation characterizes Zimnitsky's test?
11. What characterizes the Zimnitsky test in chronic renal failure?
12. What condition must be observed during the Zimnitsky test?
13. Name the pigments of normal urine.
14. What color is urine in case of bilirubinuria?
15. In what cases is the Zimnitsky test not carried out?
16. What are urates? What do they dissolve in?
17. What values of urine pH are typical for diabetes mellitus?
18. What explains the alkaline reaction of urine in acute cystitis?
1.2.2. Chemical study of urine
^ 1.2.2.1.DETERMINATION OF PROTEIN IN URINE
Normally, there is practically no protein in the urine. The presence of protein in the urine is calledproteinuria [from lat. protein protein + urina urine].
According to the place of occurrence, there are renal (renal) proteinuria, in which the protein enters the urine from the kidneys, and extrarenal (extrarenal), when the protein enters the urine from the urinary tract and genital organs.
^ Renal proteinuria divided into organic and functional.Organic renal proteinuria are observed in diseases of the kidneys with damage to their structural unit - the nephron. Organic renal proteinuria is always persistent, long-lasting and is one of the main symptoms of the disease. They are found in acute and chronic glomerulonephritis, pyelonephritis, chronic renal failure, renal amyloidosis, nephrotic syndrome.
According to the mechanism of occurrence, organic renal proteinuria are glomerular and tubular. Glomerular proteinuria occurs due to increased permeability of the renal filter and can be massive (up to 10-20 g/l of protein). Meet with glomerulonephritis, amyloidosis of the kidneys, toxic damage to the parenchyma of the kidneys. Depending on the ability of the renal filter to pass protein molecules of one size or another into the urine, glomerular proteinuria are divided into selective [from lat.selectiochoice, selection] and non-selective. At In selective proteinuria, only finely dispersed proteins with a relatively small molecular size (albumins) pass into the urine. With non-selective proteinuria, not only low-molecular, but also high-molecular proteins (globulins) pass into the urine, which indicates the severity of damage to the glomerular filter. The selectivity of proteinuria is judged by the results of the study of protein fractions of urine by electrophoresis.
Table 4
Causes and types of proteinuria
Tubular proteinuria develops with a decrease in protein reabsorption in the renal tubules (pyelonephritis). They usually do not exceed 2g/l.
Functional renal proteinuria occur in healthy people under special circumstances:
Physical overstrain - "marching" proteinuria in soldiers after forced marches, sports proteinuria in athletes, etc .;
After severe hypothermia - cold;
After eating a large amount of raw egg white (alimentary) [from lat.alimentum food];
In pregnant women in the last weeks before childbirth and in newborns of the first days of life.
All types of functional proteinuria do not last long. They quickly pass with the disappearance of the circumstances that caused them and usually do not exceed 1 g / l.
Conventionally, functional renal proteinuria also includes orthostatic and congestive proteinuria. Orthostatic proteinuria is otherwise called lordic [from lat.lordoscurvature of the spine forward]. It is observed more often in asthenic adolescents with hyperlordosis of the lower segments of the thoracic spine. At the same time, the excretion of protein in the urine does not occur constantly, but only in the vertical position of the body, hence the name - orthostatic [from lat.orthos direct + statusposition]. Orthostatic proteinuria develops as a result of pressure of the curved spine on the vessels of the kidneys.
Congestive proteinuria occurs in patients with cardiovascular diseases, when, due to circulatory disorders, blood stagnation occurs in all internal organs, including the kidneys. The amount of protein in congestive proteinuria can reach 2-5 g / l.
^ Extrarenal proteinuria develop when protein enters the urine from the urinary tract and genital organs - with inflammation of the bladder (cystitis), urethra (urethritis), vagina (colpitis). Extrarenal proteinuria depends on the admixture of secretions from the genitourinary organs (leukocytes, erythrocytes).
^ Methods for determining protein in urine. The definition of protein is included in the general analysis of urine, being its mandatory component. First, a qualitative determination of the protein is carried out using:
Unified sample with 20% solution of sulfosalicylic acid;
Express tests like "Albufan".
Normally, these tests are negative. If they give a positive result, that is, if a protein is found in the urine, then its amount is determined. For the quantitative determination of protein in urine, unified methods are used:
Turbidimetric with 3% sulfosalicylic acid solution;
Brandberg-Roberts-Stolnikov;
biuret;
With pyrogallol red.
The amount of protein in the urine is expressed in g / l. Normally, the amount of protein in the urine does not exceed 0.033 g / l.
GOST R 53079.1-2008
Group P20
NATIONAL STANDARD OF THE RUSSIAN FEDERATION
Technologies laboratory clinical
QUALITY ASSURANCE IN CLINICAL LABORATORY STUDIES
Part 1
Rules for describing research methods
medical laboratory technologies. Quality assurance of clinical laboratory tests.
Part 1. Rules for description of methods of clinical laboratory tests
OKS 11.020
Introduction date 2010-01-01
Foreword
The goals and principles of standardization in the Russian Federation are established by the Federal Law of December 27, 2002 N 184-FZ "On Technical Regulation", and the rules for the application of national standards of the Russian Federation - GOST R 1.0-2004 "Standardization in the Russian Federation. Basic provisions"
About the standard
1 DEVELOPED by the Laboratory of Problems of Clinical and Laboratory Diagnostics of the Moscow Medical Academy. I.M. Sechenov of Roszdrav, Department of Clinical Laboratory Diagnostics and Department of Biochemistry of the Russian Medical Academy of Postgraduate Education of Roszdrav, Department of Certification and Quality Control of Clinical Laboratory Research of the State Scientific Center for Preventive Medicine of Rosmedtekhnologii, Laboratory of Biochemistry of Amines and Cyclic Nucleotides of the Research Institute of Biomedical Chemistry of the Russian Academy medical sciences
2 INTRODUCED by the Technical Committee for Standardization TC 466 "Medical Technologies"
3 APPROVED AND PUT INTO EFFECT by Order of the Federal Agency for Technical Regulation and Metrology of the Russian Federation dated December 18, 2008 N 464-st
4 INTRODUCED FOR THE FIRST TIME
Information about changes to this standard is published in the annually published information index "National Standards", and the text of changes and amendments - in the monthly published information indexes "National Standards". In case of revision (replacement) or cancellation of this standard, a corresponding notice will be published in the monthly published information index "National Standards". Relevant information, notification and texts are also posted in the public information system - on the official website of the Federal Agency for Technical Regulation and Metrology on the Internet
1 area of use
1 area of use
This standard establishes the rules for the description in laboratory manuals, reference books and instructional materials for ready-made reagent kits (test systems) of clinical laboratory research methods intended for use in medical laboratories of all forms of ownership. This standard is intended for use by all organizations, institutions and enterprises, as well as individual entrepreneurs whose activities are related to the provision of medical care.
2 Normative references
This standard uses normative references to the following standards:
GOST R ISO 5725-2-2002 Accuracy (correctness and precision) of measurement methods and results. Part 2: Basic method for determining the repeatability and reproducibility of a standard measurement method
GOST R ISO 9001-2008 Quality management systems. Requirements
GOST R ISO 15189-2006 Medical laboratories. Particular requirements for quality and competence
GOST R ISO 15193-2007 Medical devices for in vitro diagnostics. Measurement of quantities in samples of biological origin. Description of reference methods for performing measurements
GOST R ISO 15195-2006 Laboratory medicine. Requirements for reference measurement laboratories
GOST R ISO/IEC 17025-2006 General requirements for the competence of testing and calibration laboratories
GOST R ISO 17511-2006 Medical products for in vitro diagnostics. Measurement of quantities in biological samples. Metrological traceability of values assigned to calibrators and control materials
GOST R ISO 18153-2006 Medical devices for in vitro diagnostics. Measurement of quantities in biological samples. Metrological traceability of catalytic concentration values of enzymes assigned to calibrators and control materials
GOST R 53022.1-2008 Clinical laboratory technologies. Requirements for the quality of clinical laboratory research. Part 1. Rules for the quality management of clinical laboratory research
GOST R 53022.2-2008 Clinical laboratory technologies. Requirements for the quality of clinical laboratory research. Part 2. Evaluation of the analytical reliability of research methods (accuracy, sensitivity, specificity)
GOST R 53022.3-2008 Clinical laboratory technologies. Requirements for the quality of clinical laboratory research. Part 3. Rules for assessing the clinical informativeness of laboratory tests
GOST R 53022.4-2008 Clinical laboratory technologies. Requirements for the quality of clinical laboratory research. Part 4. Rules for the development of requirements for the timeliness of the provision of laboratory information
GOST 7601-78 Physical optics. Terms, letter designations and definitions of basic quantities
Note - When using this standard, it is advisable to check the validity of reference standards in the public information system - on the official website of the Federal Agency for Technical Regulation and Metrology on the Internet or according to the annually published index "National Standards", which was published as of January 1 of the current year, and according to the corresponding monthly published information signs published in the current year. If the reference standard is replaced (modified), then when using this standard, you should be guided by the replacing (modified) standard. If the referenced standard is canceled without replacement, the provision in which the reference to it is given applies to the extent that this reference is not affected.
3 Rules for describing research methods and test systems intended for use in medical laboratories
3.1 General
Modern analytical capabilities of laboratory medicine are represented by a wide variety of research methods that can be used to detect and/or measure the same analyte, biological object. However, the actual values of the results of these studies performed by different methods can differ significantly from each other, which can lead to incomparability of the results of a patient examination performed in different institutions, and their erroneous interpretation, in particular, when transferring a patient from one medical institution to another. An accurate characterization of the properties of the research method, based on unified standardized data on the details of analytical procedures, the properties of the analysis tools used, the characteristics of the analytical reliability and clinical informativeness of the study, should be used when choosing and reproducing the method in clinical diagnostic laboratories, to facilitate an objective comparison of the results of using various methods and prevention of errors in the interpretation of studies conducted in the laboratories of various medical organizations.
3.2 Analytical properties of research methods
The analytical properties of the method used to study biological material are of decisive importance for the quality of the study. According to the national standards GOST R ISO 9001, GOST R ISO 15189 and GOST R ISO / IEC 17025, in a medical laboratory, quality must be ensured by analytical procedures, including the properties of the methods used.
According to the characteristics and form of expression of the result obtained (GOST R ISO 15193), methods of clinical laboratory research are divided into:
- on quantitative, which measure quantities, giving results in a scale of differences or a scale of ratios, where each value is a numerical value multiplied by a unit of measurement (in a series of values, the usual statistical parameters can be calculated: arithmetic mean, standard deviation, geometric mean and coefficient of variation );
- semi-quantitative, the results of which are expressed in an ordinal (ordinal) scale, in which values can be expressed in phrases or numbers expressing the size of the corresponding properties, and used for ranking, but differences and relationships on the scale do not matter for comparison [for a number of values there may be fractiles were calculated (including the median) and some non-parametric tests were applied, such as the Kolmogorov-Smirnov, Wilcoxon and sign tests].
Ensure that studies of samples of patient biomaterials are carried out in accordance with the needs of the clinic for information content, analytical reliability and timely receipt of research results, established by the relevant regulatory documents of the quality management system for clinical laboratory research (GOST R 53022.4);
- to ensure the comparability of the results of studies of analytes and biological objects performed in different healthcare organizations, that is, to be standardized in relation to the description and characteristics of their analytical principles and implemented technologies;
- be economically acceptable for medical organizations.
When describing research methods and test systems intended for use in clinical diagnostic laboratories of medical organizations, reliable data borrowed from special scientific literature, obtained in accredited expert laboratories, or the developers' own data regarding:
- metrological traceability of the analytical properties of the proposed methods to the properties of the reference research methods in accordance with GOST R ISO 15193 and GOST R ISO 17511 (if international reference methods are available);
- characteristics of the properties of the analysis tools used;
- evaluation of the cost-effectiveness of the practical application of the method.
3.3 Schema for a standardized description of the working method for clinical laboratory testing
3.3.1 General
This International Standard establishes a general framework for a standardized description of a test method. Descriptions of procedures for testing methods for individual analytes used in the provision of relevant simple or complex medical services are given in regulatory documents on technologies for specific medical laboratory services.
A standardized description of a clinical laboratory test method is a set of clear and complete descriptions of interrelated analytical procedures of a physical, chemical, biological nature; conditions for their implementation; reagents and equipment, the use of which, in accordance with their description, ensures reliable detection / determination of the desired analyte or biological object in a sample of biological material.
3.3.2 Standardized method description schema
A standardized method description should contain the following data:
a) the name of the method indicating the desired analyte, biological object;
b) the principle of detection or determination of an analyte, a biological object in this method;
c) the necessary chemical, biological reagents and characteristics of their physicochemical, biological properties (in the case of using separate reagents):
1) degree of purity (qualification) - for chemical reagents;
2) activity range - for enzymes, specificity - for enzyme substrates according to GOST R ISO 18153; specificity and affinity - for antibodies;
3) the composition of the components - for nutrient media;
4) detection wavelength range - for chromophores, fluorophores;
5) composition and characteristics of components, ionic strength, pH - for buffer solutions.
When using ready-made forms of reagent kits, indicate the principle of the method, the composition of the reagents, the presence of state registration, compliance with the requirements of analytical reliability, metrological traceability and commutability of the calibrator, method of application. For all reagents - the period of stability in dry form and after dissolution, features of storage conditions, degree of toxicity and biological hazard.
3.3.3 Special equipment for sample preparation and analysis
Equipment for sample preparation and analysis:
- manual,
- semi-automatic,
- automatic.
Characteristics of instruments and equipment necessary to ensure the implementation of the study:
- for dispensers - the required volume and accuracy of dosing;
- for centrifuges - the appropriate mode of operation (rpm, radius of rotation of the rotor, the need for cooling);
- for thermostats - the temperature during operation and the permissible limits of its fluctuation;
- for sterilization equipment - pressure and temperature during operation, the limits of their fluctuations;
- for anaerostats - CO content;
- for optical measuring instruments - type of photometry: absorption, flame, horizontal, vertical, reflection, turbidimetry, nephelometry, fluorometry, luminometry, time-resolved fluorometry - corresponding wavelength, slit width, light transmission, thickness of the absorbing layer of the colored solution (internal cuvette size, cm) by ; when using a thermostated cuvette - the specified temperature and the permissible limits of its fluctuations);
- for microscopes - type of microscopy, magnification, resolution according to GOST R 7601,;
- for devices for electrophoresis - the composition of the buffer solution, voltage and current strength, type of carrier;
- for devices for chromatography - the composition and characteristics of the stationary and mobile phases, the type of detector;
- for devices based on the electrochemical principle of measurement, - signal parameters, type of detector;
- for coagulometers - the principle of operation, the method of detection;
- for flow cytometers - the principle of operation, measured and calculated parameters;
- systems for image analysis should be characterized by a database, the main criteria for evaluating images.
For all instruments that are measuring instruments, their metrological characteristics must be given.
3.3.4 Analyte testing
When describing an analyte study, indicate:
a) the studied (analyzed) biological material: biological fluid, excreta, tissue;
b) specific pre-analytical precautions at the pre-laboratory and intra-laboratory stages:
1) a sample of the test material: place, method, conditions, time of taking, volume;
2) the material of the containers for taking samples, depending on the properties of the desired analyte, the procedure for processing the biomaterial;
3) additives: anticoagulants, preservatives, fixatives, gels; the volume of additives in relation to the volume of the sample;
4) storage and transportation conditions, taking into account the stability characteristics of the analyte: light, temperature, sterility, isolation from the environment, maximum storage time;
5) description of the sample preparation procedure;
c) analysis progress:
1) procedures and their conditions: reaction temperature, pH, time intervals for individual stages of the analysis procedures (incubation, duration of the reaction exit delay to the linear section, duration of the linear reaction section), type of blank sample (matrix, reagents, mixing sequence); measured material: sample (biomaterial plus reagents); the sample volume required for this measurement option, the ratio of biomaterial and reagents by volume, the stability of the reaction product;
2) calibration (calibration) procedures: calibration material, traceability of its properties to the properties of a certified standard sample (international certified reference material); construction and characterization of a calibration graph, linearity region, calibration factor, analyte detection limit, measurement range; non-linear calibration graphs; methods for calculating results;
d) assessment of the analytical reliability of the method: correctness, precision (repeatability and reproducibility), analytical sensitivity, analytical specificity; recommended materials for assessing the correctness and precision of the analytical method; comparison with the requirements for the analytical quality of the determination of a given analyte; possible sources of errors of various types, measures to eliminate them.
If there is a reference method - an assessment in relation to this method in accordance with GOST R ISO 15193. Possible interferences: drugs, hemolysis, sample icterus, lipemia;
e) assessment or calculation of the result of the study:
1) mathematical rules for calculating the result; presentation of the result: in units of the International System of Units and in traditionally used units (for quantitative methods); for semi-quantitative - in the ordinal (ordinal) scale; for non-quantitative - in the form accepted for this type of research (positive or negative result; the desired analyte was found or not found; in a descriptive (nominal) form - for cytological studies);
2) reference interval, including sex and age characteristics; analyte individuality index (to assess the applicability of matching with a reference interval); forms of pathology, for the diagnosis of which the method of studying a given analyte, biological object is intended;
3) feasibility study, taking into account the consumption of materials, the cost of working time, equipment depreciation (if possible, per unit of clinical information obtained during the study);
4) source of data on the characteristics of the method: the organization that conducted the assessment; expert laboratory; result of an interlaboratory (multicentre) method evaluation experiment; normative document of a competent national or international organization.
3.4 Requirements for describing a standardized method
When describing the analysis tools (reagent kits and instruments) of a standardized analyte test method, manufacturers should follow certain requirements.
3.4.1 The scheme of a standardized description of the research method should be detailed, since it is designed to describe the methods of various types of research used in clinical diagnostic laboratories of medical organizations.
When describing a specific method, those positions that are necessary to characterize the analytical procedures and analysis tools inherent in the study of this type should be reflected.
Note - The right to default on some characteristics of reagents in their ready-made kits, due to the protection of intellectual property, does not apply to data on the critical parameters of the method: sensitivity, specificity, correctness, metrological traceability, precision, linearity, measurement interval.
3.4.2 When describing a research method based on the use of analysis tools (reagent kits, instruments) manufactured by a certain manufacturing organization and being a closed system, the characteristics of the correctness and precision of the results obtained should be given in comparison with the reference research method or the method chosen for comparison, whose properties are compared with the reference method, data on the commutability of the calibrator.
3.4.3 With regard to the measuring instruments proposed for use in the implementation of this research method, the federal executive body in the field of technical regulation and metrology * carries out state metrological control and supervision.
________________
* Federal Law of June 26, 2008 N 102-FZ "On Ensuring the Uniformity of Measurements".
State metrological control includes:
- approval of the type of measuring instruments;
- verification of measuring instruments, including standards;
- Licensing of the activities of legal entities and individuals in the manufacture and repair of measuring instruments.
State metrological supervision is carried out:
For the release, condition and use of measuring instruments;
- certified measurement methods;
- standards of units of quantities;
- compliance with metrological rules and norms*.
________________
* The functions of state metrological control and supervision are carried out by the Federal Agency for Technical Regulation and Metrology.
The description of a standardized method for clinical laboratory research should contain information about registration with the authorized state body and about entering into the state register, for measuring instruments - about registration with the national technical regulation body, if there is a technical regulation for devices of this type - about the sign compliance.
3.4.4 Ready kits of reagents for this research method must be tested in accordance with the established procedure, meet the relevant technical requirements and must be entered in the state register, information on registration and permission for use must be presented in the description of the analyte research method.
Bibliography
ISO 8036:1998 Optics and optical instruments — Microscopes |
|
ISO 8039:1997 Optics and optical instruments — Magnifying microscopes |
|
World Health Organization. Use of anticoagulants and stability of blood, serum and plasma samples. - Geneva, 2002 |
Electronic text of the document
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M.: Standartinform, 2009
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A large number of existing diseases, individual degree in different people complicate the process of diagnosis. Often, in practice, it is not enough to use only the knowledge and skills of a doctor. In this case, clinical laboratory diagnostics helps to make the correct diagnosis. With its help, pathologies are detected at an early stage, the development of the disease is monitored, its possible course is assessed, and the effectiveness of the prescribed treatment is determined. Today, medical laboratory diagnostics is one of the fastest growing areas of medicine.
concept
Laboratory diagnostics is a medical discipline that applies standard methods for detecting and monitoring diseases, as well as searching for and studying new methods.
Clinical laboratory diagnostics greatly facilitates and allows you to choose the most effective treatment regimen.
The sub-sectors of laboratory diagnostics are:
Information obtained using various methods of clinical laboratory diagnostics reflects the course of the disease at the organ, cellular and molecular levels. Due to this, the doctor has the opportunity to timely diagnose the pathology or evaluate the result after the treatment.
Tasks
Laboratory diagnostics is designed to solve the following tasks:
- continuous search and study of new methods of biomaterial analysis;
- analysis of the functioning of all human organs and systems using existing methods;
- detection of a pathological process at all its stages;
- control over the development of pathology;
- assessment of the result of therapy;
- accurate diagnosis.
The main function of the clinical laboratory is to provide the doctor with information about the analysis of the biomaterial, comparing the results with normal values.
Today, 80% of all information important for diagnosis and treatment control is provided by the clinical laboratory.
Types of material under study
Laboratory diagnostics is a way to obtain reliable information by examining one or more types of human biological material:
- Venous blood - is taken from a large vein (mainly in the crook of the elbow).
- Arterial blood - most often taken to assess the CBS from large veins (mainly from the thigh or the area under the collarbone).
- Capillary blood - is taken for many studies from a finger.
- Plasma - it is obtained by centrifuging blood (i.e. dividing it into components).
- Serum - blood plasma after the separation of fibrinogen (a component that is an indicator of blood clotting).
- Morning urine - collected immediately after waking up, intended for general analysis.
- Daily diuresis - urine that is collected in one container during the day.
Stages
Laboratory diagnostics includes the following steps:
- preanalytical;
- analytical;
- post-analytical.
The pre-analytical stage includes:
- A person's compliance with the necessary rules for preparing for analysis.
- Documentary registration of the patient upon arrival at the medical facility.
- Signature of test tubes and other containers (for example, with urine) in the presence of the patient. The name and type of analysis are applied to them by the hand of a medical worker - he must say these data aloud to confirm their reliability by the patient.
- Subsequent processing of the taken biomaterial.
- Storage.
- transportation.
The analytical stage is the process of direct examination of the obtained biological material in the laboratory.
The post-analytical stage includes:
- Documentation of results.
- Interpretation of results.
- Formation of a report containing: data of the patient, the person who conducted the study, medical institution, laboratory, date and time of biomaterial sampling, normal clinical limits, results with relevant conclusions and comments.
Methods
The main methods of laboratory diagnostics are physicochemical. Their essence is to study the material taken for the relationship of its various properties.
Physical and chemical methods are divided into:
- optical;
- electrochemical;
- chromatographic;
- kinetic.
The optical method is most often used in clinical practice. It consists in fixing changes in a beam of light passing through a biomaterial prepared for research.
In second place in terms of the number of analyzes performed is the chromatographic method.
Probability of errors
It is important to understand that clinical laboratory diagnostics is a type of research in which errors can be made.
Each laboratory should be equipped with high-quality instruments, analyzes should be performed by highly qualified specialists.
According to statistics, the main share of errors occurs at the preanalytical stage - 50-75%, at the analytical stage - 13-23%, at the post-analytical stage - 9-30%. Measures should be taken regularly to reduce the likelihood of errors at each stage of the laboratory study.
Clinical laboratory diagnostics is one of the most informative and reliable ways to obtain information about the state of health of the body. With its help, it is possible to identify any pathologies at an early stage and take timely measures to eliminate them.