Determination of blood clotting at home. What does a blood clotting test show and how is it performed?

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 such an injury occurs, when blood oozes out, the responsible blood cells must work together to form a clot that plugs the hole.

If this does not happen on time, there is a risk of severe blood loss. If a “plug” actively forms, 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. In healthy people, the balance between liquefaction and coagulation 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 test. 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 with 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.

Analysis rate

A coagulogram or hemostasiogram is a test that determines blood clotting. bleeding when the skin is damaged - 2-3 minutes after the blood is outside the blood vessel. If this indicator deviates in one direction or another, then the doctor, through analysis, determines the characteristics of the disorders that caused this disharmony and prescribes the necessary treatment.

A coagulogram is prescribed during examination during pregnancy, if liver disease is suspected and in the preoperative or postoperative period. Also, in case of autoimmune diseases and blood clotting pathology, varicose veins and vascular pathology, a blood clotting test is indicated. The rate of coagulation directly depends on the amount of prothrombin in the blood.

Prothrombin is the name given to the protein responsible for blood clotting. It is an important component of another blood protein - thrombin. Therefore, when doing an analysis, laboratory assistants not only directly calculate the time, but also describe the chemical composition, the percentage of proteins that determine blood clotting. The normal level of prothrombin in the blood is 78-142%.

The blood contained in the blood vessels resembles water in its viscosity and fluidity. This is the main condition under which blood can perform its main function - move through the vessels, supplying all organs with oxygen, proteins, vitamins and other necessary products. But at the moment the vessel wall is damaged and it flows out of its bed, as well as when tissue thromboplastin enters it, a program is activated that ensures blood clotting. The normal thrombin time, that is, blood clotting time, is 11-17.8 s (seconds).

If the patient’s blood clotting rate is deviated towards a decrease in it, then there is a risk of large blood loss during operations or accidental injuries, as well as during childbirth and menstruation. Often this pathology occurs against the background of diabetes mellitus or during long-term treatment with indirect anticoagulants.

Men have a congenital disease called hemophilia, which is inherited. Women themselves do not suffer from this disease, but are carriers of hemophilia genes.

To restore normal coagulation, patients are prescribed direct-acting coagulants obtained from donor blood, vitamin K or the drug “Vikasol”, protamine sulfate, or the patient is given a transfusion of donor blood plasma. All these drugs and procedures slow down the process of dissolving blood clots and stop bleeding.

But if, on the contrary, the patient’s normal clotting time, as already mentioned, is 2-3 minutes, and in the patient it clots instantly? So this is wonderful! Blood loss in this case is minimal, what is the problem?

It turns out that it is precisely such deviations that are most dangerous. It is the increased coagulability that threatens the patient with strokes, thrombophlebitis, varicose veins, hemorrhoids and others.

Why does such an anomaly arise? There are many reasons. For example, excessive loss of fluid from the body with diarrhea or vomiting or poisoning or infectious intestinal diseases; with an increased volume of urination, which is typical for kidney diseases, diabetes mellitus or diabetes insipidus; when taking certain medications; for extensive burns and toxic

This syndrome is the first stage of DIC syndrome. This disease is practically impossible to treat with folk remedies. Patients are often prescribed complex inpatient treatment that must be strictly followed.

> Determination of blood clotting time

This information cannot be used for self-medication!
Consultation with a specialist is required!

Blood clotting concept

Coagulation is the process of turning blood into an elastic clot when it flows from a damaged vessel. This occurs as a result of the fact that any injury to the bloodstream provokes the transition of fibrinogen (a protein found in the blood plasma) into the insoluble protein fibrin, which, forming a clot, clogs the vessel at the site of its damage.

Blood clotting is a protective reaction that protects the body from large blood loss when the integrity of blood vessels is violated. Clotting time is determined by how quickly a blood clot forms. Blood clotting studies are carried out using specially developed methods.

Indications for the purpose of analysis

Doctors of different specialties can prescribe a test to determine blood clotting time. It is extremely necessary to undergo an examination in the following cases: pregnancy, various liver diseases, varicose veins and other pathologies of the vascular system, increased risk of thrombosis, autoimmune diseases. Determination of blood clotting time is also prescribed before planning various surgical interventions and during the recovery period after them.

How to properly prepare for research?

The material for the study is blood taken from a vein or finger. You must donate blood in the morning on an empty stomach. If there is a need to carry out the analysis at another time of the day, then at least three hours before the test you should not eat. You can't drink tea or coffee either. You can only drink plain water.

The time it takes for blood to clot is calculated from the moment it is taken for analysis until the start of clotting. Today, two main methods of performing this analysis are used - determining the blood clotting time according to Sukharev and according to Lee-White. It should be remembered that none of them determines the reason for the slowdown or acceleration of coagulation. This requires more in-depth studies of the patient’s hemostasis system.

Blood clotting according to Sukharev

To carry out this test, blood is taken from a finger, filling it with a special container-tube - the Panchenkov capillary. When collecting material, the first drop is removed with a swab, after which the capillary is filled with blood so that the height of the blood column is 25–30 mm. Next, the laboratory assistant turns on the stopwatch and tilts the horizontally located capillary in one direction and the other every 30 seconds. At the very beginning, blood moves freely inside the “tube,” but when the coagulation process begins, its movement slows down. When clotting is complete, the blood stops moving completely. The norm in this case will be the following time indicators: the beginning of the process - from 30 to 120 seconds, complete completion - from 3 to 5 minutes.

Lee-White method

During this examination, blood is taken from a vein. The technique for carrying it out is much more complicated than described above and consists in the fact that the blood clotting time is determined under strict temperature conditions (37 ° C) in two test tubes (regular and treated with silicone). In the first test tube, if all conditions are met, the blood normally clots in 5-7 minutes, in the second - in 15-25 minutes. The ratio of the second time to the first is called the contact index, the normal values ​​of which should be in the range from 1.7 to 3.0 conventional units.

Decoding the results

If, as a result of the analysis, the blood clotting time turned out to be longer than normal (reduced coagulation), this may indicate pregnancy, anemia due to acute blood loss, aplastic or hypoplastic anemia, liver pathology, impaired platelet function or a decrease in their number, poisoning with mustard gas or phosgene, leukemia, hemophilia , overdose of drugs containing acetylsalicylic acid (aspirin).

If the blood clotting time is much less than normal (thick blood), the reasons for this may be infectious diseases, hormonal imbalance, atherosclerosis, dehydration, metabolic disorders, slow blood flow due to lack of physical activity, radiation, autoimmune diseases.

According to WHO statistics, cardiovascular diseases are among the top three causes of death. Blood clots in blood vessels are one of the main factors in the development of ischemia of the heart muscle, as well as heart attacks and strokes. That is, increased blood clotting provokes acute diseases that lead to severe, often irreversible complications and death of the patient.

Causes of bleeding disorders

• Genetic. Sometimes the blood clotting mechanism has congenital defects caused by mutations in genes. Some mutations are inherited and lead to diseases such as hemophilia.
• Medicinal. Taking drugs that affect blood clotting (aspirin and other non-steroidal anti-inflammatory drugs, anticoagulants, fibrinolytics).
• Somatic. They occur against the background of other diseases (blood diseases, liver diseases, vitamin K deficiency, massive blood loss, etc.).

Most causes of bleeding disorders require immediate treatment. To detect them, you must first do a general blood test for blood clotting. Coagulation disorders can manifest themselves in two ways: increased and decreased blood clotting. The danger of increased blood clotting is explained by the high risk of blood clots in the vessels and the deterioration or complete cessation of blood supply to a tissue or organ. Reduced blood clotting, which can be congenital or acquired, poses a particular danger during injuries and operations.

Consequences of increased blood clotting

Under these conditions, the risk of blood clots is significantly increased. Inflammation of thrombosed veins leads to thrombophlebitis, accompanied by:

• pain;
• swelling;
• redness of the skin over the vein.

Blood clots in blood vessels lead to narrowing of their lumen and damage to tissue areas due to a lack of blood supply. When blood flow through a vessel is completely stopped due to a blood clot, an area deprived of blood supply appears in the tissue, which is called an ischemic focus. In this area, cells quickly die and the normal functioning of the organ is disrupted. Irreversible damage to the brain and heart are the most dangerous consequences of thrombosis.

Consequences of decreased blood clotting

With this condition, a person has an increased risk of bleeding. One of the common consequences is gastrointestinal bleeding against the background of an existing ulcer. Blood loss in such conditions due to the duration of bleeding can be very serious.

Low blood clotting increases the risk of internal bleeding, which is often noticed too late. Therefore, it is necessary to conduct a general blood test for blood clotting before any operation, as well as during treatment with drugs that have a blood thinning effect (anticoagulants, antiplatelet agents, fibrinolytics, etc.).

Who needs to determine blood clotting?

• To reduce the risk of developing vascular accidents and unexpected bleeding, it is necessary to periodically monitor the condition. This is especially important for:
• people over 40 years old;
• women during and after menopause;
• women during pregnancy;
• people who regularly take blood thinners (aspirin);
• patients suffering from varicose veins;

those preparing for surgery, etc.

The doctor must prescribe it if hemophilia is suspected (usually this disease is detected in early childhood and young adulthood) or when treating an existing thrombosis with fibrinolytic therapy and anticoagulants.

How to test your blood clotting

• Blood coagulation is a complex process consisting of several different parts and stages. Therefore, a blood clotting test should help evaluate the performance of each component link. Blood clotting occurs through the interaction of many factors along a chain. The results of a general blood test for blood clotting help determine which of the factors is impaired, which facilitates further diagnosis and choice of treatment. For example, an assessment test helps identify dysfunction of the “intrinsic” clotting pathway and determine the tendency to bleed. And it allows you to evaluate the “external” path of blood coagulation, detect liver dysfunction and vitamin K deficiency. Another important indicator that greatly helps doctors when planning operations and assessing the risk of thrombosis (including during pregnancy) is.
• It allows you to:
• determine the risk level of acute and severe cardiovascular conditions;

Conducting a general blood clotting test is an important study that helps to significantly reduce the risk of unexpected complications and mortality after illness, surgery, or childbirth. The analysis data gives the doctor the opportunity to expect objective results from the upcoming treatment and control it, and the patient a chance to protect himself from the undesirable consequences of blood clotting disorders.

Blood clotting must be normal, so hemostasis is based on equilibrium processes. It is impossible for our valuable biological fluid to coagulate - this threatens with serious, deadly complications (). On the contrary, the slow formation of a blood clot can result in uncontrolled massive bleeding, which can also lead to the death of a person.

The most complex mechanisms and reactions, involving a number of substances at one stage or another, maintain this balance and thus enable the body to cope quite quickly on its own (without the involvement of any outside help) and recover.

The rate of blood clotting cannot be determined by any one parameter, because many components that activate each other are involved in this process. In this regard, tests for blood clotting are different, where the intervals of their normal values ​​mainly depend on the method of conducting the study, and also in other cases on the gender of the person and the days, months, and years he has lived. And the reader is unlikely to be satisfied with the answer: “ Blood clotting time is 5 - 10 minutes". A lot of questions remain...

Everyone is important and everyone is needed

Stopping bleeding is based on an extremely complex mechanism, including many biochemical reactions, in which a huge number of different components are involved, where each of them plays its own specific role.

blood clotting diagram

Meanwhile, the absence or failure of at least one coagulation or anticoagulation factor can disrupt the entire process. Here are just a few examples:

• An inadequate reaction from the walls of blood vessels disrupts the blood platelets - which “feels” primary hemostasis;
• The low ability of the endothelium to synthesize and secrete inhibitors of platelet aggregation (the main one is prostacyclin) and natural anticoagulants () thickens the blood moving through the vessels, which leads to the formation in the bloodstream of absolutely unnecessary clots for the body, which for the time being can calmly “sit” attached to the wall of some -or a vessel. These become very dangerous when they break off and begin to circulate in the bloodstream - thereby creating a risk of vascular catastrophe;
• The absence of a plasma factor such as FVIII causes a sex-linked disease - A;
• Hemophilia B is found in a person if, for the same reasons (a recessive mutation in the X chromosome, which, as is known, there is only one in men), Christman factor deficiency (FIX) occurs.

In general, it all begins at the level of the damaged vascular wall, which, secreting substances necessary to ensure blood clotting, attracts blood platelets circulating in the bloodstream - platelets. For example, one that “calls” platelets to the site of an accident and promotes their adhesion to collagen, a powerful stimulator of hemostasis, must begin its activity in a timely manner and work well so that in the future one can count on the formation of a full-fledged plug.

If platelets use their functionality (adhesive-aggregation function) at the proper level, other components of primary (vascular-platelet) hemostasis quickly come into play and in a short time form a platelet plug, then in order to stop the blood flowing from the microcirculatory vessel , you can do without the special influence of other participants in the blood coagulation process. However, the body cannot cope without plasma factors to form a full-fledged plug capable of closing an injured vessel that has a wider lumen.

Thus, at the first stage (immediately after injury to the vascular wall), successive reactions begin to occur, where the activation of one factor gives impetus to bringing the others into an active state. And if something is missing somewhere or a factor turns out to be untenable, the process of blood clotting is slowed down or stops altogether.

In general, the coagulation mechanism consists of 3 phases, which must ensure:

• The formation of a complex complex of activated factors (prothrombinase) and the conversion of protein synthesized by the liver - into thrombin ( activation phase);
• Transformation of protein dissolved in the blood - factor I (, FI) into insoluble fibrin is carried out in coagulation phase;
• Completion of the coagulation process with the formation of a dense fibrin clot ( retraction phase).

Blood clotting tests

A multi-stage cascade enzymatic process, the ultimate goal of which is the formation of a clot capable of closing the “gap” in the vessel, will probably seem confusing and incomprehensible to the reader, so it will be sufficient to remind that this mechanism is provided by various coagulation factors, enzymes, Ca 2+ (ions calcium) and a variety of other components.

However, in this regard, patients are often interested in the question: how to detect if something is wrong with hemostasis or to calm down knowing that the systems are working normally? Of course, there are blood clotting tests for such purposes.

The most common specific (local) analysis of the state of hemostasis is considered to be widely known, often prescribed by therapists, cardiologists, as well as obstetricians-gynecologists, and the most informative.

Meanwhile, it should be noted that conducting such a number of tests is not always justified. This depends on many circumstances: what the doctor is looking for, at what stage of the cascade of reactions he focuses his attention, how much time medical workers have at their disposal, etc.

Simulation of the extrinsic blood clotting pathway

For example, the extrinsic pathway of coagulation activation in the laboratory can mimic what doctors call Quick's prothrombin, Quick's test, prothrombin time (PTT), or thromboplastin time (all different names for the same test). The basis of this test, which depends on factors II, V, VII, X, is the participation of tissue thromboplastin (it is added to citrate recalcified plasma during work on a blood sample).

The limits of normal values ​​in men and women of the same age do not differ and are limited to the range of 78 – 142%, however, in women expecting a child, this figure is slightly increased (but slightly!). In children, on the contrary, the norms are within lower values ​​and increase as they approach adulthood and beyond:

Meanwhile, to determine a blood clotting disorder caused by a malfunction of the internal mechanism, tissue thromboplastin is not used during the analysis - this allows the plasma to use exclusively its own reserves. In a laboratory setting, the internal mechanism is traced by waiting for blood taken from the vessels of the bloodstream to clot on its own. The onset of this complex cascade reaction coincides with the activation of the Hageman factor (factor XII). This activation is triggered by various conditions (blood contact with damaged vessel walls, cell membranes that have undergone certain changes), which is why it is called contact activation.

Contact activation also occurs outside the body, for example, when blood enters a foreign environment and comes into contact with it (contact with glass in a test tube, instruments). The removal of calcium ions from the blood does not in any way affect the launch of this mechanism, however, the process cannot end with the formation of a clot - it breaks off at the stage of activation of factor IX, where ionized calcium is no longer necessary.

The clotting time of blood, or the time during which it, having previously been in a liquid state, is poured into the form of an elastic clot, depends on the rate of conversion of the fibrinogen protein dissolved in plasma into insoluble fibrin. It (fibrin) forms threads that hold red blood cells (erythrocytes), causing them to form a bundle that closes the hole in the damaged blood vessel. Blood clotting time (1 ml taken from a vein - Lee-White method) in such cases is limited on average to 4 - 6 minutes. However, the blood clotting rate certainly has a wider range of digital (temporary) values:

1. Blood taken from a vein takes 5 to 10 minutes to form a clot;
2. The Lee-White clotting time in a glass test tube is 5–7 minutes, in a silicone test tube it extends to 12–25 minutes;
3. For blood taken from a finger, the following indicators are considered normal: the beginning is 30 seconds, the end of bleeding is 2 minutes.

An analysis reflecting the internal mechanism is used at the first suspicion of gross bleeding disorders. The test is very convenient: it is carried out quickly (while the blood is flowing or a clot is forming in a test tube), it does not require special reagents or complex equipment, and the patient does not need special preparation. Of course, blood clotting disorders discovered in this way give reason to assume a number of significant changes in the systems that ensure the normal state of hemostasis, and force further research to be carried out in order to identify the true causes of the pathology.

With an increase (lengthening) of blood clotting time, you can suspect:

• Deficiency of plasma factors intended to ensure coagulation, or their congenital inferiority, despite the fact that they are at a sufficient level in the blood;
• Serious liver pathology resulting in functional failure of the organ parenchyma;
• (in the phase when the ability of blood to clot decreases);

Blood clotting time lengthens when heparin therapy is used, so patients receiving this drug have to undergo tests indicating the state of hemostasis quite often.

The considered indicator of blood clotting decreases its values ​​(shortens):

• In the high coagulation phase () of DIC syndrome;
• For other diseases that have resulted in a pathological state of hemostasis, that is, when the patient already has blood clotting disorders and is classified as at increased risk of blood clots (thrombosis, etc.);
• In women who use oral medications containing hormones for contraception or for long-term treatment;
• In women and men taking corticosteroids (when prescribing corticosteroid drugs, age is very important - many of them in children and the elderly can cause significant changes in hemostasis, and are therefore prohibited for use in this group).

In general, the norms differ little

Indicators of blood clotting (normal) in women, men and children (meaning one age for each category), in principle, differ little, although certain indicators in women change physiologically (before, during and after menstruation, during pregnancy), therefore, the sex of an adult is still taken into account when conducting laboratory tests. In addition, for women during the period of bearing a child, certain parameters even have to shift somewhat, because the body has to stop bleeding after childbirth, so the coagulation system begins to prepare in advance. An exception with regard to some indicators of blood clotting is the category of children in the first days of life, for example, in newborns the PTT is a couple or three times higher than in adult males and females (the norm for adults is 11 - 15 seconds), and in premature infants the prothrombin time increases for 3 – 5 seconds. True, by about the 4th day of life, PTT decreases and corresponds to the blood clotting norm of adults.

The table below will help the reader to get acquainted with the norms of individual indicators of blood clotting, and, possibly, compare them with their own parameters (if the test was carried out relatively recently and there is a form recording the results of the study on hand):

Laboratory test	Normal blood clotting index values	Material used
Platelets: Among women In men In children	180 – 320 x 10 9 /l 200 – 400 x 10 9 /l 150 – 350 x 10 9 /l	Capillary blood (from a finger)
Clotting time: According to Sukharev According to Lee-White	Start – 30 - 120 seconds, end – 3 - 5 minutes 5 - 10 minutes	Capillary Blood taken from a vein
Duration of bleeding according to Duke	no more than 4 minutes	blood from finger
Thrombin time(indicator of fibrinogen conversion to fibrin)	12 – 20 seconds	venous
PTI (prothrombin index): Blood from a finger Blood from a vein	90 – 105%	Capillary Venous
APTT (activated partial thromboplastin time, kaolin-kephalin time)	35 - 50 seconds (does not correlate with gender and age)	blood from a vein
Fibinogen: In adult men and women In women in the last month of the third trimester of pregnancy In children of the first days of life	2.0 – 4.0 g/l 1.25 – 3.0 g/l	Deoxygenated blood

In conclusion, I would like to draw the attention of our regular (and new, of course) readers: perhaps reading the review article will not fully satisfy the interest of patients affected by hemostatic pathology. People who are faced with a similar problem for the first time, as a rule, want to get as much information as possible about the systems that ensure stopping bleeding at the right time and preventing the formation of dangerous clots, so they begin to look for information on the Internet. Well, you shouldn’t rush - in other sections of our website a detailed (and, most importantly, correct) description of each of the indicators of the state of hemostasis is given, the range of normal values ​​is indicated, and indications and preparation for analysis are also described.

Video: simply about blood clotting

Video: report on blood clotting tests

One of the presenters will answer your question.

Currently answering questions: A. Olesya Valerievna, Ph.D., teacher at a medical university