What is the blood clotting test called? Blood test for coagulation: indicators, interpretation. How to suspect deterioration of coagulation hemostasis

Blood is an important component of the human body, performing several important functions simultaneously:

This list can be continued for some time, because the value of blood is too high. Its normal functioning can be achieved if specific conditions are met:

• the ratio of various blood elements must maintain a certain balance,
• the blood formula must meet established standards,
• its coagulability should be equal to the reference values.

Today we will cover a topic that specifically affects blood clotting, and we will find out the name of the analysis that determines this value.

Each of us could observe this complex process more than once in our lives, because no one is immune from scratches, cuts, wounds and other damage. When an injury like this occurs, where blood oozes out, the responsible blood cells must with common effort form a clot that plugs the hole.

If this does not happen on time, there is a risk of severe blood loss. In case of active formation of a “plug”, it can develop into a blood clot that disrupts blood circulation, which means that certain parts of the body will begin to deplete due to a lack of useful elements. U healthy people the balance between liquefaction and coagulability is always maintained in balance; in pathologies, it can be disrupted and lead to irreversible consequences and even death.

You can find out your blood clotting ability from a coagulogram - a special laboratory research. Sometimes it is also called a hemostasiogram. The notation in the analysis that is worth paying attention to is:

• Prothrombin (prothrombin time);
• Thrombin time;
• Fibrinogen.

Analysis transcript

You need to check your blood clotting ability:

A blood coagulogram is also indicated for monitoring long-term treatment indirect anticoagulants.

The main indicators responsible for the result of the blood clotting test:

• Clotting time (abbreviated BC) is the number of seconds (minutes) during which a clot of fibrin manages to form, starting from the moment the material is taken for analysis.
• Prothrombin index (signed on the form as PTI) - this figure indicates the percentage ratio of the clotting time of the test plasma to the reference plasma.
• Thrombin time (TT) is the time required for fibrinogen to convert into fibrin.
• Activated partial thromboplastin time (abbreviated as APTT) is the time period required for a blood clot to form when exposed to calcium chloride and other substances.
• Fibrinogen - displays the concentration of protein dissolved in blood plasma.

Norm of analysis

When the surface of a vessel is damaged, a person begins to bleed. To stop it, the body has a property called clotting. Depending on the various reasons it can either increase or decrease. Excessive coagulation can lead to the formation of blood clots, and insufficient coagulation can lead to bleeding.

The system that maintains the correct balance is called hemostasis.

• A blood clotting test must be done when:
• thrombosis;
• disorders of the cardiovascular system;
• pathological processes in the liver;
• varicose veins;
• before surgery;
• treatment with leeches;
• when prescribing anticoagulants;

during pregnancy.

A blood clotting test is called a coagulogram. Blood from a vein must be donated on an empty stomach. After you have eaten, at least 8 hours must pass. The study is carried out within 1 day. In the functioning of hemostasis, individual parameters are distinguished, the determination of which is determined by a biochemical blood test.

The coagulogram is deciphered by a specialist. Biochemical analysis

• blood is divided into the study of primary and secondary hemostasis. A description of the following is included in studies to study primary hemostasis:
• bleeding time;
• platelet aggregation;
• platelet adhesion;

blood clotting time during analysis.

• The study of secondary hemostasis includes:
• prothrombin index (PTI);
• thrombin time;
• amount of fibrinogen;

APTT.

Parameters and their standards

If you have had a blood test, deciphering its results gives a picture of your condition. Bleeding time (BT) is measured from the onset of bleeding when the capillary is punctured until the blood stops flowing. The normal VC is 2-3 minutes. An increase in this indicator may be a consequence of hereditary thrombocytopenia, and some medications may also be the cause. Platelet aggregation is the ability of platelets to come together. The aggregation rate in the analysis is 0-20%. Reduced aggregation may be a consequence of a lack of platelets in the blood or some other disease that affects circulatory system . And for diseases such as heart attack,, atherosclerosis, thrombosis, aggregation, exceeds the norm.

Platelet adhesion is their ability to seal the resulting damage on the vessel wall. Under normal conditions, the adhesiveness index ranges from 20 to 50%. With weak kidney function or leukemia, adhesiveness decreases.

The clotting time during the analysis is calculated from the puncture of the vessel and the collection of blood from it until the formation of a fibrin clot in it. When the test is taken from a vein, the blood clotting rate is from 5 to 10 minutes. And when studying capillary blood - 0.5-2 minutes. A decrease in these parameters occurs when using oral contraceptives or after suffering major bleeding. Exceeding the norm is possible if there is a deviation in the functioning of the kidneys or a diagnosis such as hemophilia.

PTI is the ratio of the clotting period of the analyzed plasma to the period corresponding to the norm. This ratio is called the prothrombin index. The coagulogram shows the amount of PTI.

Normal PTI ranges from 93 to 107%. Prothrombin is a protein from which thrombin is synthesized, which causes fibrinogen to produce fibrin. Fibrin collects platelets at the site of rupture blood vessel, plugging the damage. Prothrombin is formed in the liver. Therefore, PTI can be used to evaluate its performance. A reduced prothrombin index indicates that blood clotting is insufficient. This happens when there is not enough vitamin K, if a person takes diuretics or acetylsalicylic acid. Another cause may be enterocolitis or dysbacteriosis. This also happens at the beginning of pregnancy, and at the end, on the contrary, clotting increases. An increase in PTI causes a risk of thrombosis.

Thrombin time (TV). During this period, a clot is formed - a thrombus. Thrombin time shows the rate at which fibrinogen turns into fibrin. The usual rate for this process is a period of 16 to 18 seconds. Fibrinogen: A soluble protein that interacts with another substance called thrombin. The result is a new protein, fibrin. It is of great importance in the functioning of the blood clotting mechanism.

The amount of fibrinogen. A biochemical blood test, deciphering it, allows you to determine the amount of fibrinogen. Its normal values ​​will be 2-4 g/l. Fibrinogen is synthesized by the liver. With hepatitis, cirrhosis, toxicosis, lack of vitamins C and B12, the fibrinogen content is reduced. And during a heart attack or occurring in the body inflammatory processes And infectious diseases- rises.

APTT factor - in the analysis, abbreviated activated partial thromboplasty time. Its normal range is from 30 to 40 seconds. According to the experience of different clinical laboratories, this value may vary slightly in one direction or another. During this period, the blood freezes during analysis in the laboratory, when it is exposed to certain reagents. APTT increases when functions performed by the liver are impaired or when there is a lack of vitamin K. In patients with hemophilia, this indicator is lower.

Blood clotting rate – fixed indicator, and any deviation is dangerous to health, and, in some cases, life.

It has many functions, the main ones of which are nutrition of all organs and systems of the body, transport of oxygen and nutrients to them.

Nutrition will be disrupted - problems will start. Organs will begin to fail.

How the indicator is determined, and what the consequences may be for deviations of various kinds, we will consider further.

The study of blood clotting is called a coagulogram. It includes six types of studies, analyzing big picture in which the doctor makes a conclusion about the patient’s state of hemostasis and the expected consequences.

Each age has its own.

A blood clotting test can be taken from a finger prick ( arterial), and from a vein ( venous). The tests will be the same, the only difference will be in the results of the test. The venous one takes a little longer to coagulate. The doctor will take this fact into account when making a diagnosis.

Ask your question to a clinical laboratory diagnostics doctor

Anna Poniaeva. Graduated from Nizhny Novgorod medical academy(2007-2014) and Residency in Clinical Laboratory Diagnostics (2014-2016).

Plus deoxygenated blood allows you to conduct a wider range of analyzes and analyze hemostasis from all sides.

To evaluate the work of platelets, it is enough to take an arterial sample from a finger.

In any case, we will consider all methods sequentially, since one includes the other.

The hemostasis analyzed in the study is a system that maintains a constant blood concentration through reverse chain reactions.

The sample taken is immediately subjected to in vitro testing.

The patient is free at this time and will receive information about himself in a few hours.

The following tests are carried out (we will list all 8, but 6 are considered basic):

1. Blood test for normal clotting time. The test is general and gives a very broad concept, without additional details. Determined visually.
2. Prothrombin index. Or in other words – prothrombin time. External coagulation is assessed. Already gives a deeper understanding of the clinical picture.
3. Thrombin time. This is an end-phase coagulation assay. This indicator can presumably diagnose DIC syndrome and increased bilirubin.
4. Study of fibrinogen activity. It increases with inflammation of internal organs, or simply extensive inflammation, with liver pathologies and the normal physiological course of pregnancy.
5. APTT – activated partial thromboplastin time. The process is activated by the addition of potassium chloride. The tendency to hypercoagulation is determined.
6. Plasma recalcification time. Calcium derivatives are added to the plasma and the time of clot formation is noted if they are present in the solution.
7. Plasma tolerance to heparin. Heparin containing calcium salts is added to the fibrin clot that has already formed. The time spent dissolving the clot will be the result.
8. Retraction of a blood clot. Time to separate the clot from the whey.

This is a list of experiments carried out with biomaterial and provided to the doctor to confirm the diagnosis or its refutation.

To decipher the analysis, take into account the value physiological significance, which very individual for everyone ages and genders.

Blood clotting test	Indicator, norm	Biomaterial under study
Platelet count	Adults – 150-400 hl Children – 150-350 hl	Capillary
Blood clotting, normal	According to Sukharev: started after 30-120 seconds; End in 3-5 minutes; According to Lee-White 5-10 min.	Capillary; Venous.
PTI (prothrombin index)	Capillary: 93-107% Venous: 90-105%	Capillary Venous.
Thrombin time	15-20 sec	Venous
According to Duque	No more than 4 minutes	From the finger
APTT	35-50 sec universal	From Vienna
Fibrinogen content	Adults: 2-4 hl Children: 1.25-3.0 hl	From Vienna

Normal coagulability in pregnant women will be physiologically rejected downwards, as it thickens as it approaches childbirth, to prevent large blood loss.

There is no specific indicator; it is determined by the doctor taking into account the course of pregnancy and the condition of the patient herself.

In older people, the indicators are often the same as in average adults, but an increase in blood density is still possible. It is also determined individually, taking into account concomitant diseases.

Watch a useful video on this topic

Determination methods

Laboratory diagnostics of the indicator is done in several ways.

• Determining the norm of blood clotting time according to Sukharev: the biomaterial is distilled into a capillary tube closer to the center and tilted every half a minute, trying to pour it out. As soon as it stops pouring out, this will be the final result.
• Normal clotting time according to Lee-White: the sample is taken into three 1 ml tubes, heated to 37 degrees and periodically tilted. As soon as the blood remains motionless, the result is obtained.
• Duque's method. Very unusual, conducted directly with the patient. The soft part of the ear is pierced, and a piece of filter paper is periodically applied to it. When there are no traces left, the test is over.

There are many other ways: Moravico, Mas Magro and etc.

These are the simplest and most effective.

Deviations

Deviations can be downward or upward.

Decreased coagulation is often caused by an overdose of thinning drugs, or hereditary disease– hemophilia.

There is a risk fatal outcome for bleeding, even if this is a clotting test.

If the interpretation of the clotting test shows increased result– this threatens thrombus formation, which means heart attack, stroke and possible acute insufficiency some organs.

There are several reasons for the increase:

• Dehydration;
• Metabolic syndrome;
• Impaired absorption of ions;
• Renal and liver failure;
• Autoimmune diseases.

The condition is extremely dangerous and requires immediate treatment.

You should consult a specialist.

Prevention

Prevention of any deviation from the norm is adequate control over your health, timely delivery of analysis to determine the norm of blood clotting indicator and healthy image life.

Frequent examinations and even greater monitoring by a specialist are indicated for pregnant women.

Maintain thickness biological fluids within reason, drinking hygiene will also help. 2 liters per day is a universal norm for everyone.

The water should be filtered and not boiled, so it will be better absorbed.

Conclusion

Coagulation time and coagulation rate are determined in the laboratory and help the doctor make a diagnosis. Timely prescribed treatment will prevent the consequences that this deviation entails.

Blood is the component of the human body that allows it to function as an integral system. It contains all the information about the functioning of organs and tissues and transmits it between them. Thus, they constantly adapt to changing environmental conditions and internal environment body. A huge place in the functional usefulness of such interaction is occupied by blood clotting, which determines its ability not only to supply organs nutrients, but also convey to them information about the state of the body as a whole.

Basics of Keeping Blood Fluid

Blood maintains the constancy of its structure. This means that, on the one hand, it must be thick enough so as not to sweat through the vascular wall under the influence of pressure in the vessels, which is pumped up by the heart. On the other hand, too thick blood will not be able to circulate through capillary networks and other vascular structures of the microvasculature. Therefore, it must have a balance that is controlled by the system of coagulation (coagulation) and anticoagulation (anticoagulation). Collectively this is called coagulation homeostasis. As long as both systems are in harmonious interaction, the body functions normally.

Important to remember! Impaired blood clotting can cause many diseases, primarily those associated with blood vessels and the heart. But this is not its only meaning. It almost always changes its coagulation properties against the background of severe pathology!

Blood coagulation and the ability to form a clot are affected by:

• State vascular walls. Violation of the structure of the inner layer of arteries triggers processes of increased coagulation;
• The number and functional usefulness of platelets. They are the main overseers of the integrity of the vascular bed and are the first to initiate the process of accelerated coagulation;
• Concentration and state of plasma coagulation factors. Most of them are synthesized by the liver with the participation of vitamin K and the vascular endothelium. An increase or decrease in their number leads to an increase or decrease in blood clotting;
• Concentrations of plasma factors of the anticoagulation system (antithrombin, heparin, antiplasmin and others). The more there are, the thinner the blood.

Basic tests and their normal values

The ability of blood to clot can be determined using laboratory tests. For their implementation, both capillary (from a finger) and. Each of the tests requires a certain type of blood and will determine the condition of individual parts of the hemostasis (coagulation) system. The names and types of main analyzes and their norms are given in the form of a separate table.

Analysis name	Indicator norm	What kind of blood is used
Platelet level test	In men and women 150-400 g/l	Capillary (finger sampling)
	In children 150-350 g/l
Clotting time	Norm according to Sukharev: beginning – 30-120 seconds; end – between 3 and 5 minutes;	Capillary
	Norm according to Lee-White 5-10 minutes	From Vienna
	Should not exceed 4 minutes	From the finger
Thrombin time (TV)	12-20 seconds	From Vienna
Prothrombin index (PTI)	Capillary blood 93-107%	Finger analysis
	Venous blood 90-105%	Analysis from a vein
Activated partial thromboplastin time (aPTT)	For all age groups, regardless of gender 35-50 seconds	Venous
Fibrinogen	Adults 2-4 g/l; in a child’s first days of life 1.25-3.0 g/l	From Vienna

Platelets are the main blood cells responsible for blood clotting.

Not everything is listed in the table possible indicators blood coagulation system. There are a lot of them and they are all included in the scope of the coagulogram. But diagnosing coagulation problems always begins with the methods described in this article. All additional and more specific tests are prescribed only if it is necessary to obtain more detailed information about the hemostatic system.

Important to remember! Coagulation rates in women are subject to large fluctuations. Their rate can be significantly, but briefly reduced during menstruation or increased while taking hormonal drugs!

General rules for conducting analyzes

Regardless of what coagulogram indicator will be examined, and what kind of blood is needed for it, the subject must adhere to certain rules:

1. Blood sampling is carried out in the morning;
2. Avoid eating 8-10 hours before the test, alcoholic drinks- per day;
3. Avoid smoking 3-4 hours before the test;
4. Immediately before taking the test, it is advisable for the body to remain at rest for several minutes.

Blood collection and analysis depends on its type. Those methods that require capillary blood are carried out immediately after puncturing the skin of one of the fingers with a scarifier or a special needle. If venous blood is needed for research, about 20 ml of it is taken according to the general rules in one of the peripheral veins. After collection, it must be delivered to the laboratory within 2 hours and centrifuged to obtain plasma. It is this part of the blood that is examined during the determination of coagulogram parameters.

The essence of the main analyzes

The norm of any analysis is an average indicator that needs to be able to be correctly compared with the results of the blood being tested. In this case, all those natural factors that can naturally influence the result of the coagulation study must be taken into account. These include:

• Women, especially during menstruation. All their indicators may be reduced. During pregnancy there is a tendency to increased coagulability;
• Taking oral hormonal contraceptives promotes blood clotting;
• Taking anticoagulants and other blood thinners;
• Dehydration and exposure high temperatures causes conditions in which the norm of coagulation indicators may be exceeded;
• Major injuries, surgeries, transfusions of blood and its components.

The essence and diagnostic capabilities of the main indicators of blood coagulation are given in the table.

Coagulability index	What does it mean
Platelet level	Reflects the number of cells that are responsible for starting blood clotting when the integrity of the vascular wall is violated.
Coagulation time according to Sukharev	Reflects the ability of capillary blood to form a clot when it is placed in a thin glass capillary with its smooth alternating inclination in opposite directions. The time when the movement of blood becomes difficult and the time when a persistent clot forms is noted.
Lee-White clotting time	The analysis is carried out by analogy with Sukharev’s technique. The only difference is that this analysis requires venous blood.
Thrombin time	Shows the state of the last phase of blood coagulation. Indirectly indicates the concentration of administered drugs and natural factors of the coagulation and anticoagulation systems.
Duration of bleeding according to Duke	Indicates the body's ability to stop blood loss. The method is the simplest of all known. It is tested by recording the time it takes for blood to stop flowing from a small wound after the skin of a finger is punctured.
Prothrombin index	Reflects the ability of plasma coagulation factors in the blood being tested to form a clot when tissue coagulation factors produced by platelets are added to them. It is measured as a percentage of the prothrombin time (in seconds) of the test subject to the normal prothrombin time.
APTT	It differs from the prothrombin index in that it shows only the activity of plasma coagulation factors without the participation of platelets.
Fibrinogen	Determination of the concentration of a specific blood protein that is responsible for strengthening the blood clot.

The main indicators of blood clotting are associated with the activity of plasma factors of the coagulation and anticoagulation systems

Why is coagulation disrupted and what are its consequences?

The norm of indicators of the hemostasis system can be exceeded for the following reasons: pathological reasons:

1. Increased platelet levels due to their excessive production bone marrow;
2. Infectious-toxic and septic diseases;
3. Any intoxication that occurs against the background of severe pathology internal organs;
4. Widespread atherosclerotic vascular lesions;
5. Congenital and genetic abnormalities of anticoagulant system factors;
6. Artificial valves hearts and vascular prostheses;
7. Autoimmune diseases;
8. Endocrine pathology with metabolic disorders in the body;
9. Blood stagnation due to heart failure and physical inactivity;
10. The first phase of DIC syndrome.

Indicators of clotting tests may be lower than the generally accepted norm. The following reasons will lead to this:

1. Thrombocytopenia;
2. Hemophilia and other inherited defects of clotting factors;
3. Hemolytic anemia;
4. Leukemia;
5. Decompensated liver failure with cirrhosis;
6. Insufficient amount of calcium and vitamin K in the body;
7. Overdose and treatment with anticoagulants (heparin, warfarin, drugs acetylsalicylic acid);
8. The last phase of DIC syndrome.

Important to remember! Increased blood clotting is dangerous due to the accelerated formation of blood clots in the vessels, which can cause thrombosis of the arteries and veins of internal organs, limbs and brain. Decreased coagulability is fraught with an increased risk of massive and profuse bleeding!

Research and correct interpretation data from blood clotting tests allows you to determine all the risks in relation to potential opportunity emergence vascular diseases, as well as monitor the effectiveness of blood thinners used and their dosage.

Blood is one of the most important fluids in human body, all life processes occurring in working organs depend on it. The blood itself also has several functions, and clotting is one of them. Both insufficient and excessive blood clotting can lead to the death of the body. To check this blood characteristic, you need to undergo a test for coagulation of the substance, that is, take a blood test.

As a result of this examination, an assessment is made of the blood's ability to thicken (clotting). This examination is also known as a hemostasiogram or coagulogram. The analysis shows a picture where the main indicators will be the values ​​of the blood systems (coagulation and anticoagulation).

How and why blood clots

The process of blood clotting is quite complex. For example, at the site of a fresh injury (cut, wound and other similar injuries), blood cells should group and form a kind of “plug,” a blood clot that prevents fluid from flowing out of the damaged vessel. The thrombus stops unauthorized blood loss, while protecting the vessel from infection and mechanical particles, in a way “gluing” the edges of damaged tissue. But the blood must maintain its liquid state, otherwise all processes in the body will be weakened.

To maintain such characteristics of the blood, the hemostasis mechanism is simultaneously accompanied by two completely opposite processes: liquefaction and coagulation of the fluid. The normal state of blood fluid is a balance between both processes. So on the coagulogram, by plotting graphs, you can see how this balance is maintained.

How is a blood clotting test performed?

Blood is drawn from a vein. Then the sample is placed in a test tube, into which a special substance is added that prevents blood from thickening. Next, the sample is examined and a number of basic and auxiliary parameters are determined.

Main analysis parameters:

1. Prothrombin time (PTT), prothrombin index (PTI) or international normalized ratio (INR). You can carry out either one of these tests or all of them (depending on the equipment of the laboratory). In principle, they all have identical meaning and produce similar indicators, which can then be compared with each other. This test characterizes the extrinsic clotting pathway of the fluid.
2. Activated partial thrombin time (aPTT) - testing internal path stop bleeding.
3. Thrombin time (TT) – clot formation. This stage of blood coagulation is the last; the presence of a blood clot indicates the presence of fibrin in the fluid.

The latter is a product formed by the interaction of the soluble protein fibrinogen and a substance called thrombin. Fibrin becomes an insoluble protein substance, which forms a thrombus (clot). The formation of such a clot may also indicate an inflammatory process occurring in the body.

Additional analysis options:

1. Antithrombin III is a factor of the anticoagulant system. Its deficiency in the blood leads to thrombosis of internal organs, varicose veins, and so on.
2. D-dimer. This product causes natural destruction of the clot. This test is carried out at early diagnosis thrombosis, preventive treatment of thromboembolism of the pulmonary artery and other vessels.
3. Protein C is a factor of the anticoagulant system. A deficiency of the substance can provoke the occurrence of internal blood clots after surgical intervention(surgeries), after childbirth and the like.
4. Lupus anticoagulant (LA) is tested if antiphospholipid syndrome is suspected.

Indications for analysis

A blood clotting test is prescribed in the following cases:

• It is necessary to identify the causes of uncontrolled bleeding or blood clots.
• DIC syndrome.
• Diagnosis of thromboembolism, hemophilia, antiphospholipid syndrome.
• Checking the body's response to heparin and other drugs, the use of which may affect coagulation processes.
• Before the start and after the end surgery, as well as when using thrombolysis, coronary angiography and other manipulations.

Preparing the body for blood sampling

Blood should be donated in the morning and on an empty stomach, preferably from the moment last appointment food has passed at least 8-12 hours. If the patient smokes, it is better not to smoke at all in the evening. If the patient is taking any medications, this must be reported.

Decoding the analysis results

Standards for the main indicators of a blood test for coagulation:

• PTV 11–16 sec.;
• PTI 80–120%;
• INR 0.8–1.2 units;
• APTT 21–35 sec;
• TV 14–21 sec.;
• fibrinogen in adults 2–4 g/l;
• fibrinogen in newborns 1.25–3.00 g/l.

Testing blood for clotting is a rather complex, multi-stage process. Often it is simply impossible to do without a specialized assessment. Although each factor is tested separately, the overall picture is assessed: the influence of substances and processes on each other, the effectiveness of the therapy.

If blood clotting processes are affected by targeted medications therapeutic action, then the coagulogram picture will change significantly (due to targeted treatment). For example, taking warfarin leads to an increase in the INR level up to 4.5 units (whereas the norm is 2-3 units). This helps reduce the risk of blood clots.

Indicators of blood test testing may vary in different laboratory conditions. different meaning. This depends on the composition of the reagents used for research in a particular institution. Therefore it is important when full examination try to get tested in the same laboratory.

Features of blood test indicators for coagulation in pregnant women

Every woman experiences pregnancy differently. For some, everything is fine, for others, pathologies are detected. Pregnant women must undergo coagulation.

Note that due to constant changes in a woman’s body during pregnancy, blood characteristics also undergo the same changes. Thus, in the first trimester of pregnancy, slow blood clotting is observed, and the closer to the birth of pregnancy, the more this ability of the blood increases. This natural process, So female body prepares to reduce blood loss during childbirth.