Thrombin time, take a thrombin time test in Rostov-on-Don at a competitive price

Thrombin is one of the main enzymes involved in the regulation of the blood coagulation system. It is responsible for stabilizing the blood clot, which is vital during bleeding. When the amount of thrombin in the blood changes, clotting problems and hemostasis may occur, because thrombin is responsible specifically for the stage of blood clot formation. The time it takes for a clot to form under real conditions is called thrombin time.

Thrombin time in the laboratory is the period during which fibrinogen is converted into fibrin in plasma mixed with sodium citrate, calcium and thrombin. There may be several indications for prescribing an analysis:

for liver pathologies;
to identify a lack of fibrinogen in the body;
to monitor heparin treatment;
before operations and surgical interventions;
with spontaneous termination of pregnancy up to 20 weeks.

Clinical signs of insufficient fibrinogen are increased bleeding and a tendency to form blood clots. Patients usually report the following symptoms:

slow healing of the skin surface;
heavy bleeding (including heavy menstruation);
frequent occurrence of hematomas;
rash.

Description of blood test for thrombin time

Thrombin time is a certain period of time required for the formation of a fibrin clot from fibrin, which occurs under the influence of thrombin.
The formation of fibrin from fibrinogen represents an assessment of the final step in blood clotting. Thrombin time is the period required for the conversion of fibrinogen to fibrin, which occurs in citrated plasma as a result of the addition of calcium and thrombin. The process of fibrin clot formation can take a different period of time. This is directly related to the amount of fibrinogen, as well as its functionality. The presence of anticoagulants in the blood also plays an important role.

Thrombin time is necessary to determine dysfibrinogenemia, as well as to assess blood anticoagulant activity. Prolonged thrombin time can be observed in the case of a strong decrease in the level of fibrinogen in the blood (up to 0.5 g/l or less). Also, prolonged thrombin time can be detected in the presence of various fibrin degradation products in the blood (for example, with disseminated intravascular coagulation or thrombolytic therapy). Prolonged thrombin time is a possible consequence of the presence of abnormal forms of fibrinogen in the circulatory system. This is often observed in patients with congenital pathologies and liver diseases.

The presence of direct anticoagulants, especially heparin, causes prolongation of thrombin time. This occurs due to the neutralization of added thrombin by the heparin-antithrombin complex.

Indirect anticoagulants do not change the test results. The cause of prolongation of thrombin time is also often the presence of autoantibodies to thrombin or the presence of paraproteins in the blood. Paraproteins prevent the polymerization of fibrin monomers.

*Note: Thrombin is a proteolytic enzyme and the main reagent of the test. It can be used exclusively to convert soluble plasma fibrinogen into insoluble fibrinogen.

Test material:

Plasma (anticoagulant - sodium citrate).

References

Clinical guidelines for the diagnosis and treatment of rare blood clotting disorders: hereditary deficiency of factors X, II, VII, 2021.
Volkova, P.O., Zolotavina M.L., Didenko S.N. and others. Dependence of polymorphism of blood coagulation genes and blood group and rhesus affiliations in women. — Scientific almanac, 2021. — No. 1-2(15). — P.455-458.
Sturov, V.G., Plyushkin, V.A., Anmut, S.Ya. and others. The final stage of blood coagulation: modern clinical and laboratory diagnosis of dysfibrinogenemia syndrome. - Thrombosis, hemostasis and rheology, 2008. - No. 2 (34). — P.8-15.
Undas, A. Determination of fibrinogen and thrombin time (TT). — Methods in molecular biology, 2021.

Indications for prescribing a thrombin time test

Determination of fibrinogen deficiency or defect.
Assessing the general condition of the patient with disseminated intravascular coagulation (DIC syndrome).
Liver pathology.
Assessing the effectiveness of therapy with heparin, fibrinolytic or thrombolytic drugs.
Determination of the presence of fibrin/fibrinogen degradation products in the blood.
Determination of fibrinogen deficiency and dysfibrinogenemia in congenital or acquired form.

Complexes with this research

Miscarriage Identification of the main causes of miscarriage 29,050 ₽ Composition
Entry into IVF Examination when a woman enters the IVF procedure 15,030 ₽ Composition

Examination during pregnancy. 1st trimester 10,390 ₽ Composition

IN OTHER COMPLEXES

Female infertility RUB 9,790
Extended coagulogram RUB 2,730
Examination during pregnancy. 3rd trimester 5,730 ₽
Pregnancy planning. Clinical indicators RUB 3,880
Coagulogram RUB 1,110

Interpretation of thrombin time test results

An increase in the values (extension) of prothrombin time is possible with:

congenital or acquired hypofibrinogenemia, causing a decrease in fibrinogen concentration to 0.5 g/l and below. Hypofibrinogenemia often develops as a consequence of liver pathology, as well as in the course of a disruption in the process of “protein nutrition” of the body. Accompanied by a significant increase in fibrinogen levels - up to 4 g/l or more;
hereditary or acquired dysfibrinogenemia, often resulting from liver pathologies. Represents molecular defects in fibrinogen;
DIC syndrome, fibrinolytic therapy, accompanied by an increased content of fibrinogen degradation products (fibrin);
the presence of direct anticoagulants in the blood, such as heparin, hirudin, synthetic antithrombins;
hyperbilirubinemia;
paraproteinemia;
uremia, accompanied by the production of antibodies to thrombin and, in some cases, lupus anticoagulant;
multiforme myeloma.

A decrease in values (shortening) of thrombin time is possible with:

Stage I of DIC syndrome, accompanied by an increased risk of thrombosis;
a significant increase in fibrinogen in the blood.

Hemostasiogram (screening)

Hemostasis is the stopping of bleeding caused by damage to the vessel wall. Violation of its integrity can occur due to:

physical impact;
action of hemodynamic factors;
exposure to chemicals;
metabolic disorders;
inflammatory process;
actions of immune complexes;
various diseases, etc.

The hemostasis system is a functional system of the body that is responsible for ensuring the constancy of its internal environment, preventing and stopping bleeding, dissolving blood clots that have completed their task, maintaining circulating blood in a liquid state, and normal resistance of the walls of microvessels. The hemostasis system is involved in the healing process of damaged tissues, in inflammatory processes, regulation of local blood flow and transcapillary exchange.

The hemostasis system includes two links - coagulation and anticoagulation, on the interaction and balance of which its functionality depends. Its structural components are:

coagulation hemostasis;
platelet-vascular hemostasis;
anticoagulant system;
fibrinolytic system;
complement system, kallikrein-kinin system, proteins, blood plasma lipoproteins.

There are three ways of blood clotting:

internal - realized exclusively due to enzymes and cofactors present in the blood plasma;
external - realized as a result of the action of enzymes, blood cofactors + tissue factor (TF - blood coagulation factor III), which is normally absent in the blood;
general, including the formation of fibrin and its stabilization.

Stopping bleeding takes place in several stages:

spasm of the vessel wall;
formation of aggregates by platelets (“white thrombus”);
blood plasma coagulation (“red thrombus”);
clot dissolution (fibrinolysis).

The complex study “Hemostasiogram” is a set of tests designed to study the state of the hemostasis system, and includes the determination of the following indicators:

activated partial thromboplastin time (aPTT, item 512);
prothrombin according to Quick, prothrombin time, INR (item 605);
fibrinogen (item 606);
thrombin time (item 683).

Description of the studied indicators

APTT

APTT (activated partial thromboplastin time) is an indicator whose value reflects the time of formation of a blood clot after the gradual addition of portioned thromboplastins, reagents that trigger the reaction, to the sample of platelet-free citrate plasma with a kaolin-kephalin mixture and calcium chloride. Kaolin, in contact with plasma, stimulates the synthesis of active factor XII - XIIa, providing a surface for the action of high molecular weight kininogen, kallikrein and factor XIIa. The role of phospholipids in this process is the formation of complexes with active factor X (Xa) and prothrombin. After a certain time, CaCl2 is added to the mixture, through which the initiation of coagulation along the internal pathway is simulated.

By determining APTT:

the functionality of coagulation factors is assessed;
a deficiency or impaired functionality of such coagulation factors and contact factors of the internal pathway as VIII, IX, XI, XII, prekallikrein, high-molecular kininogens, as well as factors of the general coagulation pathway (including I, II, V, X) is detected;
The presence of coagulation inhibitors (substances that slow down/inhibit the blood clotting process) is determined.

The duration of the reaction and the time of clot formation are affected by changes in concentration:

high molecular weight kininogen;
prekallikrein;
coagulation factors VIII, XI, XII;
factors V, X (to a slightly lesser extent);
prothrombin;
fibrinogen.

A decrease in clot formation time is an indicator of the risk of thrombosis. A reduction in clot formation time by more than 5 seconds is an indicator of hypercoagulation (blood thickening).

Prolongation of the time of clot formation is a sign of hypocoagulation (a blood clotting disorder in which there is a tendency to repeated bleeding and hemorrhage, both spontaneous and due to injury). The development of hypocoagulation is promoted by:

deficiency of factors II, V, VIII, IX, X, XI, XII;
fibrinogen deficiency;
liver pathologies;
vitamin K deficiency;
presence of heparin;
lupus anticoagulant;
pathological inhibitors of fibrin polymerization (these can be myeloma proteins, fibrin degradation products, etc.) or other blood clotting inhibitors.

The reason for the prolongation (increase in duration) of the APTT time may be a decrease of 30-40% of the norm in the level of any of the coagulation factors.

APTT reflects the influence of blood coagulation factors on clot formation and is most often performed to:

determining the effectiveness of the internal blood coagulation pathway;
monitoring the effectiveness of heparin therapy.
identifying possible abnormalities in the functioning of the blood coagulation system before surgery in order to avoid subsequent complications;
diagnosis of a number of blood diseases, liver pathologies that cause disruption of the production of proteins involved in blood clotting;
diagnosis of DIC syndrome (in combination with other laboratory tests).

Prothrombin according to Quick

Quick prothrombin reflects the activity of the prothrombin complex of the patient's plasma in comparison with the measured prothrombin time of control plasma.

To determine the indicator, a calibration graph of the dependence of prothrombin time on the percentage of prothrombin complex factors is used (factors of the prothrombin complex are blood coagulation factors - II (prothrombin), VII, IX and X, and proteins SI and S, which take part in the activation reactions of precursor proteins leading to the formation of thrombin). Values at different dilutions of control plasma are used to construct the curve.

Prothrombin according to Quick allows you to get the most accurate result, especially in the area of low values, so this method is by far the most used.

Prothrombin time

Prothrombin time is measured in seconds and shows how long it takes for plasma to clot after adding a mixture of thromboplastin and calcium to it. Test results obtained in different laboratories are not suitable for comparison, since they use different equipment and thromboplastin of different activity and origin.

Quick's prothrombin and prothrombin time reflect the presence/absence of a deficiency of clotting factors (prothrombin complex) and the functionality of the extrinsic coagulation pathway (i.e., the ability of blood to form a clot when tissue is damaged). If the quantity and quality of fibrinogen, a soluble plasma protein that is directly involved in the formation of a blood clot (thrombus) after damage to the vessel wall, is normal, then the result of the study will depend on the content of factors II, V, VII, X. It is their presence that determines the activity of prothrombin complex. The liver is responsible for producing these clotting factors, so this test can be used to determine its ability to produce them. This process is directly dependent on the level of vitamin K. Since indirect-acting anticoagulants (ANDA) act as its antagonists, the analysis is also used to monitor treatment using them.

INR

INR (International Normalized Ratio) or in the Latin version of the abbreviation INR (International Normalized Ratio) is an additional method for obtaining the results of a prothrombin test, allowing for monitoring the condition of patients who are taking indirect anticoagulants.

INR is defined as the ratio of the patient's prothrombin time to the normal mean prothrombin time, raised to the power of the International Sensitivity Index (ISI - International Sensitivity Index of thromboplastin).

INR = (patient's prothrombin time/normal mean prothrombin time) ISI

MIC is the sensitivity coefficient of thromboplastin, which brings it to the international standard. INR is essentially a method of mathematical correction by which prothrombin time, measured using thromboplastins with different sensitivities, is standardized.

Reference INR values in various cases depend on the purpose of taking indirect anticoagulants and are determined by the attending physician. The use of indirect anticoagulants can be carried out:

for the prevention of deep vein thrombosis;
in the treatment of deep vein thrombosis and pulmonary thromboembolism (acute blockage of a blood vessel by a thrombus);
with critical ischemia (insufficient blood supply) of the legs;
for the prevention of thromboembolism in patients with atrial fibrillation (a heart rhythm disorder characterized by chaotic contraction of the muscle fibers of the heart) and heart defects (defects in the structure);
when installing bioprosthetic heart valves;
for secondary prevention of myocardial infarction, if the use of aspirin is contraindicated;
for the prevention of thrombosis in persons with antiphospholipid syndrome (a pathology in which there is an increased production of antibodies to phospholipids - substances that are building materials for cells);
when installing mechanical prosthetic heart valves.

At the same time, the reference INR values recommended by the World Health Organization are 2-3 for the first six cases, and 2.5-3.5 for the last two.

A significant increase in INR indicates hypocoagulation (tendency to bleeding), which is an indication for reducing the dose of anticoagulants used. An INR value below the established norm indicates that the risk of thrombosis remains increased, is evidence of the ineffectiveness of the treatment used, and is an indication for dose adjustment of the anticoagulant.

INR and prothrombin according to Quick are inversely proportional - the lower the prothrombin according to Quick, the higher the INR.

Fibrinogen

Fibrinogen (according to the international nomenclature - factor I of the blood coagulation system) is a two-component protein (glycoprotein), the molecular weight of which is 340,000 Da. It is an earlier form of fibrin, a protein that forms the basis of a clot when blood clots. Fibrinogen is produced in the liver, from which it then enters the blood with other components involved in blood clotting. The half-life of the protein is about 100 hours. The functions of fibrinogen as a blood clotting factor include:

ensuring a number of fibrinolysis reactions (the process of dissolving blood clots) due to the binding of excess thrombin (this determines its another name - antithrombin I);
activation of plasminogen - a circulating inactive proenzyme that is a precursor of the plasmin protein, which plays an important role in fibrinolysis, and, in turn, is a precursor of angiostatin - a protein that suppresses the formation and growth of blood vessels (angiogenesis).

Fibrinogen is converted to fibrin, which is the basis of the blood clot that forms after damage to a blood vessel. The fibrin algorithm consists of the formation of its monomers, polymerization, and stabilization of the clot. As a result of these processes, insoluble fibrin I is formed. Its threads intertwine, forming a kind of framework, which, together with platelets, forms a clot (or thrombus). The blood clot remains in the damaged area until it is completely healed.

When blood clotting factors work correctly and there is a sufficient number of platelets, a stable blood clot is formed. In case of deficiency of factors or their incorrect interaction, thrombosis or bleeding may occur.

Determination of fibrinogen levels is included in a comprehensive analysis of blood clotting indicators. In addition, the study of protein concentration is part of a preoperative examination, prenatal diagnosis (comprehensive prenatal diagnosis, the purpose of which is to identify pathologies in a child during intrauterine development), diagnosis of heart and vascular diseases. It is important to know that an increase in fibrinogen concentration, even within normal limits, can cause a relapse of cardiovascular diseases. In pregnant women, the indicator goes beyond the upper limit for physiological reasons and can reach 6 g/l in the last trimester.

An increased level of fibrinogen does not require special treatment in two cases: during pregnancy and during inflammation, because after stabilizing the body’s condition, it returns to normal levels.

Thrombin time

Thrombin time (TT) is the time period during which fibrinogen is converted into fibrin in citrated plasma with thrombin and calcium introduced into it and a blood clot is formed. The rate of formation of a fibrin clot is directly influenced by the quantity and quality of fibrinogen and the presence of anticoagulants in the blood. This test monitors the final stage of blood clotting.

Thrombin (proteolytic (protein-splitting) enzyme, blood coagulation factor IIa) - is formed when a vessel is damaged as a result of the interaction of other coagulation factors. It is one of the main regulators of the blood coagulation process and the main reagent used in this study. Only under its influence does the conversion of soluble plasma fibrinogen into insoluble fibrin and stabilization of the blood clot occur, which is necessary to stop bleeding.

Blood thickening is a complex process that takes place in several stages involving a number of components. The sequence of blood clot formation is as follows:

under the influence of thrombin, fibrinopeptides A and B are cleaved from the A alpha and B beta chains of fibrinogen, and fibrin monomer is formed;
fibrin complexes in the form of filaments are spontaneously formed from fibrin monomer molecules;
Due to the activation of blood coagulation factor VIII and the plasma transglutaminase enzyme by thrombin, the resulting soluble fibrin complexes become insoluble.

The form of fibrin obtained as a result of the reaction is stable and durable - it practically does not collapse. In addition to polymerized fibrin, the clot also contains blood cells - platelets and erythrocytes.

If the qualitative (structural and functional) or quantitative characteristics of fibrinogen are violated, excessive or insufficient fibrin production occurs, which can cause thrombosis, excessive bleeding, or a combination of both pathologies, and when laboratory tests are performed, prolongation (extension) or reduction of thrombin time.

The most common causes of bleeding disorders are:

hypo- and afibrinogenemia – pathologies in which fibrinogen deficiency is observed;
dysfibrinogenemia – pathologies in which the functions and structure of fibrinogen are impaired.

When conducting laboratory tests, characteristic signs of dysfibrinogenemia are:

prolongation of thrombin time (the main symptom of these conditions);
increased connection of platelets with each other (their aggregation).

These conditions do not affect the concentration of fibrinogen in the blood. With them, such laboratory parameters as:

activated partial thromboplastin time;
the level of soluble fibrinogen-monomer complexes (RFMC - item 681), which are fragments of blood clots;
the level of D-dimer (position 679), a fibrin breakdown product found in the blood after cleavage of the fibrin network under the influence of plasmin.

The cause of hereditary dysfibrinogenemia may be:

afibrinogenemia, characterized by the absolute absence of fibrinogen in the blood plasma;
hypofibrinogenemia, characterized by a small amount of fibrinogen in the blood, but sufficient to carry out the blood clotting process.

As a result of research, about 400 mutations have been identified that cause a structural disorder in which amino acids are replaced in the fibrinogen sequence. With such a replacement, its activity decreases, interaction with thrombin is disrupted, or further polymerization of fibrin is stopped. In more than half of cases, dysfibrinogenemia is asymptomatic. The presence of a pathology is discovered by accidental detection of abnormalities in laboratory tests or by its detection in one of the family members. Cases of increased bleeding are detected in 25% of patients (their cause may be trauma, surgery, or the postpartum period). 20% of patients have a tendency to thrombosis (venous to a greater extent than arterial). In 27% of cases, a combination of both conditions is observed. Another form of hereditary pathology is hereditary amyloidosis, in which fibrinogen is deposited in the kidney tissues in the form of amyloid, leading to acute renal failure.

Acquired dysfibrinogenemia is often caused by liver pathologies:

cirrhosis;
chronic active hepatitis;
acute liver failure;
obstructive diseases;
primary hepatocellular liver cancer (hepatocellular carcinoma, hepatoma).

In all of these diseases, an excess amount of sialic acids is added to fibrinogen. The resulting modification of fibrinogen has a significant negative charge, which creates an obstacle to fibrin polymerization.

Improper liver function is the cause of multiple bleeding disorders, manifested by increased bleeding. The thrombin time test can determine whether dysfibrinogenemia is the cause of bleeding.

The production of abnormal fibrinogen is also carried out by some forms of a number of tumors, such as:

squamous cell carcinoma of the cervix;
breast adenocarcinoma;
hypernephroma (kidney cancer);
hepatoma (liver cancer).

The activity of fibrinogen may decrease in diseases characterized by the formation of antibodies that interact with it (these include, in particular, systemic lupus erythematosus and multiple myeloma). Autoantibodies to fibrinogen or paraproteins (structurally abnormal and functionally defective proteins produced by tumors) also prolong thrombin time because they prevent fibrin monomers from polymerizing.

The most common cause of acquired hypofibrinogenemia (a decrease in the level of the coagulation factor fibrinogen in the blood) is disseminated intravascular coagulation syndrome (DIC syndrome or thrombohemorrhagic syndrome) - a systemic pathological process in which fibrin microthrombi are formed in the microcircular vessels in large quantities, and there is a high consumption of blood factors and platelets. The pathology is characterized by a combination of thrombosis with blood incoagulability, which causes multiple massive hemorrhages. DIC syndrome is not an independent disease. Its development is determined by the complication of other pathologies. DIC syndrome can be acute or chronic. The acute form of the syndrome can develop against the background

a) infectious diseases:

sepsis caused by Escherichia coli (E. coli);
human immunodeficiency virus (HIV infection);
cytomegalovirus infection;
malaria;

b) acute myeloblastic leukemia;

c) complications of pregnancy and childbirth:

premature placental abruption;
eclampsia;
amniotic fluid embolism;

d) extensive burns;

e) transfusion of large quantities of blood or its components, etc.

Chronic DIC syndrome can develop:

for solid tumors;
for chronic leukemia;
for myeloproliferative diseases;
for rheumatoid arthritis;
with Raynaud's disease;
with Crohn's disease;
with nonspecific ulcerative colitis;
with myocardial infarction;
in case of intrauterine fetal death, etc.

Clinically, a decrease in fibrinogen concentration may manifest itself as a tendency to thrombosis or increased bleeding. For example, pathology may manifest itself:

difficult to stop heavy bleeding;
poor wound healing;
extremely heavy menstruation (menorrhagia);
spontaneous appearance of bruises;
rash.

The impetus for the development of DIC syndrome in all of the above pathological conditions is the excessive intake of tissue factor (blood clotting factor III; thromboplastin) into the blood, which causes the formation of multiple microthrombi in the vessels of various organs (in particular, lungs, liver, brain, kidneys) . Their presence leads to dysfunction of body systems and multiple organ failure, which manifests itself clinically. As the syndrome develops, the consumption of fibrinogen and other blood coagulation factors increases significantly, which leads to their deficiency and a change from a state of hypercoagulation (increased blood clotting) to a state of hypocoagulation (reduced coagulation) and massive bleeding. Medical practice shows that patients quite often experience the simultaneous presence of hyper- and hypocoagulation, which makes the division of DIC into periods quite relative, and its diagnosis very difficult. Therefore, determining the thrombin time and conducting other laboratory tests is necessary and important to determine the likelihood of development, early detection and monitoring of the progress of treatment of DIC syndrome.

Extension of clot formation time may indicate:

low (less than 0.5 g/l) fibrinogen level;
about the presence of fibrin degradation products in the blood (in DIC syndrome, in the process of restoring blood flow in the vessels, when defective fibrinogen appears in the blood due to hereditary or acquired pathologies).

The time for clot formation also increases in the presence of direct-acting anticoagulants in the blood, such as heparin, which neutralize the effect of thrombin introduced into the plasma. The presence of indirect anticoagulants does not have any effect on the test result.

Changes in indicator during pregnancy

Monitoring this indicator of blood clotting is extremely important during pregnancy, especially when pregnant women are taking medications that affect the blood clotting process. Normally, thrombin time during pregnancy is increased and ranges from 18 to 25 seconds. Imbalance of the coagulation and anticoagulation systems can lead to serious complications during pregnancy. The most dangerous is disseminated intravascular coagulation (DIC), which develops as a result of activation of the coagulation system on the one hand and the fibrinolysis system on the other. In pregnant women, DIC syndrome can be caused by various reasons:

premature placental abruption with bleeding, which is caused by a decrease in the concentration of coagulation factors in the plasma.
amniotic fluid embolism – leads to shock and acute respiratory failure and the development of disseminated intravascular coagulation syndrome due to the entry into the bloodstream of a large amount of tissue thromboplastin, which triggers the blood clotting process;
endometritis, as a complication after childbirth, can lead to the development of a fulminant form of DIC syndrome.

A common cause of miscarriage is antiphospholipid syndrome, which is characterized by arterial and venous thrombosis, leading to disturbances in intrauterine development of the fetus. Pregnant women with APS are at high risk of spontaneous abortion and miscarriage. In the clinic, determination of thrombin time is used for monitoring during heparin therapy and fibrinolytic therapy, for diagnosing activation of fibrinolysis, as well as indirect diagnosis of dysfibrinogenemia.

time, blood clot

Thrombin time is normal

To measure thrombin time, the following reference values are accepted:

10.3 – 16.6 seconds.

Factors influencing the result

Sometimes the results may be distorted. There are a number of reasons for this:

Age (in newborns, thrombin time is normally prolonged);
Violations of the rules for preparing for a coagulogram;
Violations of the algorithm for blood collection, its transportation and storage;
Incompetence of laboratory workers;
Taking interfering drugs;
Transfusion of frozen plasma shortly before the test (hides quantitative and structural fibrinogen abnormalities);
Menstruation (reduces clotting rates);
Acute febrile syndrome in a patient during venous blood sampling;
Recent injuries, wounds, burns, surgery.