Activated partial thromboplastin time. What is APTT in a blood test? APTT is elevated what to do

Update: December 2018

A coagulogram (otherwise a hemostasiogram) is a special study that shows how good or bad a person's blood coagulation is.

This analysis plays a very important role in determining a person's condition. Its indicators help to predict how the operation or childbirth will go, whether the patient will survive, whether it is possible to stop the bleeding of the wounded.

More about blood clotting

Blood is a special liquid that has the ability not only to circulate through the vessels, but also to form dense clots (blood clots). This quality allows her to close gaps in medium and small arteries and veins, sometimes even imperceptibly to humans. Preservation of the liquid state and blood clotting is regulated by the hemostasis system. The coagulation system or hemostasis system consists of three components:

• vascular cells, and specifically the inner layer (endothelium) - when the vessel wall is damaged or ruptured, a number of biologically active substances(nitric oxide, prostacyclin, thrombomodulin), which trigger thrombus formation;
• platelets are platelets that are the first to rush to the site of injury. They stick together and try to close the wound (forming a primary hemostatic plug). If platelets cannot stop bleeding, plasma clotting factors turn on;
• plasma factors- the hemostasis system includes 15 factors (many are enzymes), which, due to a number of chemical reactions, form a dense fibrin clot that finally stops bleeding.

A feature of coagulation factors is that almost all of them are formed in the liver with the participation of vitamin K. Human hemostasis is also controlled by anticoagulant and fibrinolytic systems. Their main function is to prevent spontaneous thrombosis.

Indication for the appointment of a hemostasiogram

How to prepare for a coagulogram?

• the material is taken strictly on an empty stomach, it is desirable that the previous meal was at least 12 hours ago;
• on the eve it is recommended not to eat spicy, fatty, smoked foods, alcohol;
• it is forbidden to smoke before taking the material;
• it is advisable to stop taking anticoagulants of direct and indirect action, since their presence in the blood can distort the coagulation parameters;
• if the intake of such medications is vital for the patient, it is necessary to warn the laboratory assistant who will consider the analysis.

How is a blood coagulation test done?

• the material is taken with a dry sterile syringe or a Vacutainer vacuum blood collection system;
• blood sampling should be carried out with a needle with a wide lumen without the use of a tourniquet;
• vein puncture should be atraumatic, otherwise a lot of tissue thromboplastin will get into the test tube, which will distort the results;
• the laboratory assistant fills 2 test tubes with material, while sending only the second one for examination;
• the tube must contain a special coagulant (sodium citrate).

Where can I get tested?

This study can be carried out in any private or public clinic or laboratory that has the necessary reagents. Hemostasiogram is a difficult analysis to perform and requires sufficient qualification of laboratory assistants. The cost of the examination varies from 1000 to 3000 rubles, the price depends on the number of factors to be determined.

How many days is a coagulogram done?

To obtain the results of the study, the laboratory doctor usually conducts a series of chemical reactions that require a certain time. It usually takes 1-2 business days. One thing also depends on the workload of the laboratory, the availability of reagents, and the work of the courier.

Norm of coagulogram

Deciphering the coagulogram

Prothrombin time (PT)

PT is the time of thrombin clot formation if calcium and thromboplastin are added to the plasma. The indicator reflects the 1st and 2nd phase of plasma coagulation and the activity of 2,5,7 and 10 factors. Norms of prothrombin time (PT) at different ages:

• Newborn premature babies - 14-19 sec;
• Newborn full-term babies - 13-17 seconds;
• Young children - 13-16 sec;
• Older children - 12-16 seconds;
• Adults - 11-15 sec.

Therapy with anticoagulants is considered effective if the PT increases at least 1.5-2 times.

INR

INR or prothrombin coefficient is the ratio of the patient's PV to the PV of the control tube. This indicator was introduced by the World Health Organization in 1983 to streamline the work of laboratories, since each laboratory uses different thromboplastin reagents. The main purpose of determining the INR is to control the intake of indirect anticoagulants by patients.

Reasons for changes in PV and INR:

APTT (activated partial thrombin time, cephalin-kaolin time)

APTT is a measure of the effectiveness of plasma factors in stopping bleeding. In fact, APTT reflects the internal pathway of hemostasis, how quickly a fibrin clot forms. This is the most sensitive and accurate indicator of the hemostasiogram. The value of APTT, first of all, depends on the reagents-activators used by the doctor, and the indicator may vary in different laboratories. A shortening of the APTT indicates increased coagulability, the possibility of the formation of blood clots. And its lengthening indicates a decrease in hemostasis.

Why does the APTT value change?

Activated recalcification time

AVR is the time required for the formation of fibrin in plasma saturated with calcium and platelets. The indicator reflects how much the plasma and cellular parts of hemostasis interact with each other. Its value may vary depending on the reagents used in the laboratory. AVR lengthens with a decrease in the number of platelets (thrombocytopenia) and a change in their quality (thrombocytopathies), hemophilia. A shortening of the AVR indicates a tendency to form blood clots.

Prothrombin index

The prothrombin index or PTI is the ratio of the ideal prothrombin time to the patient's prothrombin time multiplied by 100%. Currently, this indicator is considered obsolete, instead, doctors recommend determining the INR. The indicator, like the INR, levels out those differences in the results of PT that occur due to different thromboplastin activity in different laboratories.

Under what pathologies does the indicator change?

thrombin time

Thrombin time shows the final stage of hemostasis. TB characterizes the length of time required for the formation of a fibrin clot in plasma if thrombin is added to it. It is always determined together with APTT and PT for the control of fibrinolytic and heparin therapy, diagnostics congenital pathologies fibrinogen.

What diseases affect thrombin time?

fibrinogen

Fibrinogen is the first factor in blood clotting. This protein is formed in the liver and under the influence of the Hageman factor is converted into insoluble fibrin. Fibrinogen belongs to the acute phase proteins, its concentration increases in plasma during infections, trauma, and stress.

Why does the level of fibrinogen in the blood change?

RFMC

RFMK (soluble fibrin-monomer complexes) are intermediate products of fibrin clot breakdown due to fibrinolysis. RFMK is very quickly excreted from the blood plasma, the indicator is very difficult to determine. Its diagnostic value lies in the early diagnosis of DIC. Also RFMC increases with:

• thrombosis of various localization (thromboembolism pulmonary artery, deep veins of the extremities);
• in the postoperative period;
• complications of pregnancy (preeclampsia, preeclampsia);
• acute and chronic renal failure;
• sepsis;
• shocks;
• systemic connective tissue pathologies and others.

Antithrombin III

Antithrombin III is a physiological anticoagulant. Structurally, it is a glycoprotein that inhibits thrombin and a number of coagulation factors (9,10,12). The main site of its synthesis is the liver cells. Indicators of antithrombin III at different ages:

• Newborns - 40-80%
• Children under 10 years old - 60-100%
• Children from 10 to 16 years old - 80-120%
• Adults - 75-125%.

Why does its content in the blood change?

D-dimer

D-dimer is the residue of split fibrin strands. This indicator reflects both the work of the coagulation system (if there is a lot of D-dimer in the blood, it means that a lot of fibrin has been split) and the function of the anticoagulant system. The indicator is contained in the blood for about 6 hours after formation, so the material must be immediately examined in the laboratory.

Diagnostic value is only an increase in the level of the indicator, which occurs when:

• thrombosis and thromboembolism of arteries and veins;
• liver diseases;
• extensive hematomas;
• ischemic heart disease and myocardial infarction;
• in the postoperative period;
• prolonged smoking;
• DIC;
• seropositive rheumatoid arthritis.

Bleeding time

Method of determination: pierces the earlobe with a medical needle or a scarifier. Then we note the time until the blood stops. Doctors evaluate only the lengthening of the indicator, since its shortening indicates an incorrectly conducted study. Bleeding time is lengthened due to:

• lack of platelets in the blood (thrombocytopenia);
• hemophilia A, B and C;
• liver damage from alcohol;
• hemorrhagic fevers (Crimea-Congo, with renal syndrome);
• thrombocytopenia and thrombocytopathy;
• overdose of indirect anticoagulants and anticoagulants.

Blood clotting time according to Lee-White and Mass and Magro

This study shows the time required for the formation of a blood clot. The method is very simple to perform: blood is taken from a vein. The material is poured into a dry, sterile tube. Timed until it appears visible to the eye blood clot. In violation of the hemostatic system, the clotting time can be shortened and lengthened. In some pathological conditions (DIC, hemophilia), a clot may not form at all.

Coagulogram during pregnancy

During pregnancy, a woman's body undergoes colossal changes that affect all systems, including the hemostasis system. These changes are due to the appearance of an additional circle of blood circulation (uteroplacental) and a change in hormonal status (prevalence over estrogens).

During the period of bearing a child, the activity of coagulation factors increases, especially 7,8,10 and fibrinogen. There is a deposition of fibrin fragments on the walls of the vessels of the placental-uterine system. The fibrinolysis system is suppressed. Thus, the woman's body tries to insure itself in the event of uterine bleeding and miscarriage, prevents placental abruption and the formation of intravascular blood clots.

Indicators of hemostasis during pregnancy

In pathological pregnancy (early and late gestosis), disturbances in the regulation of blood coagulation occur. The life of platelets is shortened, fibrinolytic activity increases. If a woman does not go to the doctor and does not treat gestosis, a very formidable complication occurs - DIC.

DIC or disseminated intravascular coagulation syndrome consists of 3 stages:

• hypercoagulation- the formation of many small blood clots, impaired blood circulation between the mother and fetus;
• hypocoagulation - over time, clotting factors are depleted in the blood, blood clots disintegrate;
• acoagulation - lack of blood clotting uterine bleeding, which threatens the life of the mother, the fetus in most cases dies.

A blood test can reveal a predisposition to the formation of blood clots and bleeding. To do this, it is necessary to determine the APTT. This is an indicator of blood clotting ability. This diagnosis will help to avoid severe pathological conditions(for example, internal bleeding, myocardial infarction, stroke, and others). Particular attention is paid to this indicator in children and the elderly. Consider what APTC is, what are the norms of the indicator, the causes of deviations above and below the norm, and what this means in a blood test (coagulogram).

APTT - what is it?

Activated partial thromboplastin time (APTT) is the time it takes for a blood clot to form when examining biological material. To do this, activators (calcium chloride, kaolin suspension, phospholipids) are added to the test tube with blood plasma.

With the help of APTT, the state of the body's hemostasis system is assessed. Moreover, APTT indicates precisely its internal mechanism. Therefore, it is used for:

With a decrease or increase in this time, pathological processes occur in the body, which must be identified and treated in a timely manner.

Coagulogram analysis

A set of indicators by which one can judge the process of blood coagulation is called a coagulogram. Activated partial thromboplastin time is evaluated in conjunction with other indicators:

• PT (prothrombin time);
• PTI (prothrombin index);
• fibrinogen;
• Prothrombin according to Quick.

These indicators make up the coagulogram. With their help, you can fully evaluate the work of both internal and external mechanisms of blood coagulation. It should be noted that all of them are indicative, and only according to these indicators it is impossible to make an accurate diagnosis. This requires a complete examination.

Blood for the study of the coagulogram is taken from a vein. In order for the result to be reliable, it is necessary to properly prepare for blood donation. The patient must follow several recommendations:

• On the eve and immediately before blood sampling, it is necessary to abandon heavy and intense physical work, including sports;
• Avoid stressful situations, have a good rest and sleep;
• The analysis must be taken on an empty stomach, that is, the last meal should be 10-12 hours before the procedure. On the eve, it is best to limit yourself to a light dinner;
• In the morning you can not drink any drinks except clean water. It is recommended to drink it 20 minutes before the test;
• Warn medical worker about anticoagulant treatment, if it cannot be interrupted for the duration of the study;
• Do not drink alcoholic beverages the night before.

What can affect the results of the analysis

Any blood test, including the APTT test, can be false positive or false negative. The results of the analysis are influenced by multiple factors, such as:

• Laboratory error, or rather the human factor. So the wrong ratio of blood and reagents in the test tube can affect the result. The correct ratio is 9 parts of blood and 1 part of reagents. If the laboratory assistant increases the amount of one or the second, then the result may be more or less than the norm;
• Presence fatty foods in the diet. Excess fat makes the blood more viscous and thick;
• The period of menstruation in women;
• Smoking;
• Pregnancy. In women in position this indicator below the norm;
• The use of oral hormonal contraceptives(decrease in index).

The rate of APTT in a blood test and decoding of the analysis

APTT is measured in seconds. However, it should be borne in mind that the norm may differ for different laboratories. It depends on the equipment and the type of reagents that are used for blood testing in a particular clinical diagnostic laboratory.

APTT depends on age physical condition and nutrition of the patient.

The norm of APTT in a blood test in women, men and children:

• In adults, the APTT is slightly lower than in children and ranges from 24 to 40 seconds;
• In newborns, this figure is slightly increased, the limits of the norm range from 25 to 44 seconds;
• At premature newborn the baby has the highest values, they are 4 - 5 seconds more than the adult indicators.

It should be remembered that in women, APTT may decrease even in a state of full health. The reason for this is her physiological state: pregnancy or menstruation. This prevents large blood loss during menstruation and the development of severe complications in pregnant women. In this case, no correction is required.

If a person's APTT is below normal even for 5 seconds, then his blood coagulates very quickly. This can lead to thrombosis. In the case when an increase in values ​​is detected, we can talk about a violation of hemostasis. The blood does not clot for a long time. This causes massive blood loss.

APTT during pregnancy

The normal aPTT during pregnancy is 15 to 20 seconds. That is, their blood coagulates faster than other people. Such an analysis is carried out at least 3 times during the period of bearing a baby (in each trimester). If the indicator deviates from the norm up or down, then constant monitoring and treatment is required. Otherwise, various complications arise.

If the APTT is lowered during pregnancy, then there may be:

• Thrombosis of the vessels of the placenta;
• Premature detachment of the placenta.

If the APTT is elevated during pregnancy, the following complications develop:

• Bleeding during pregnancy leading to miscarriage
• Bleeding during childbirth, because of which not only the woman suffers, but also the child, as he experiences severe oxygen starvation;
• Massive blood loss in the early postpartum period;
• Lethal outcome in severe cases.

Special care is needed for pregnant women who:

• History of several miscarriages;
• Hypertension of the uterus;
• The threat of termination of pregnancy;
• Late toxicosis (edema and increased blood pressure).

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Causes of increased APTT

If the result turned out to be above the norm, then it is necessary to find the cause and carry out timely treatment. Reasons why APTT is elevated:

• Hemophilia is hereditary pathology blood coagulation system;
• Malignant neoplasms of various localization;
• Disseminated intravascular coagulation syndrome second or third stage;
• Treatment with anticoagulants. These medicines thin the blood;
• von Willebrand's disease is a hereditary disease that manifests itself in multiple bleeding of various localizations. In this case, the destruction of the vascular wall occurs;
• SLE (systemic lupus erythematosus). Most often, this pathology is recorded in women. Of the 10 patients, only 1 is a man;
• Heparin injections;
• After a large amount of blood transfusion;
• Lack of vitamin K in the body. It is necessary for the formation of prothrombin. Most of it is produced by its own intestinal microflora;
• Severe liver pathology;
• Chronic course of glamerulonephritis;
• Connective tissue pathology;
• Deficiency of various blood clotting factors;
• Decrease in the concentration of fibrinogen in the blood;
• antiphospholipid syndrome.

Causes of a reduced APTT

In the case when the activated partial thromboplastin time is shortened, the formation of thrombi of various sizes and locations occurs. This is evidence of hypercoagulability (rapid clotting). The reasons for the reduced APTT are as follows:

• Hypercoagulable phase (first) of the syndrome of disseminated intravascular coagulation. DIC is an acquired pathology associated with excessive production of blood clotting factors. This disease is characterized by the formation of multiple blood clots. In this regard, various internal organs are affected;
• Pregnancy. Smallest values determined at the end of the gestational period;
• The use of hormonal oral contraceptives. Before their appointment, it is necessary to conduct a blood test;
• Lack of antihemophilic globulin;
• Treatment by some medicines(vitamin K, corticosteroids, barbiturates);
• An increase in the number of red blood cells - polycythemia;
• Violation of the technique of blood sampling, that is, unsuccessful puncture of a vein. In this case, tissue thromboplastin enters the blood and the biological sample is contaminated;
• period of menstruation.

What is APTT? Why is this blood test taken and what is the APTT norm in different categories of patients? What if your APTT is above normal or low, what processes in the body can these deviations tell about? Let's figure out together what this means. Of course, we will not self-diagnose ourselves, but the information below will certainly help you ask your doctor the right questions.

What is this indicator

APTT - what is it? Activated partial thromboplastin time is usually called the time during which blood coagulates under the influence of special reagents. That is, in the process of studying, the process of coagulation is modeled. To conduct the test, special substances are added to the blood sample, such as calcium chloride, koalin-kephalin mixture, and others. The purpose of the analysis is to identify a deficiency of blood coagulation factors or retarder substances (hereinafter referred to as inhibitors) of the coagulation process.

A blood test for APTT shows how efficiently our hemostasis system works. The results of the APTT analysis are a diagnostically significant factor in suspected hemophilia, monitoring the condition of patients undergoing heparin and hirudin therapy.

What are the indications for an APTT blood test?

The appointment of this blood test for coagulation is typical for situations with suspected thrombosis, thromboembolism, heart attacks, bleeding and / or predisposition to them, hemophilia, DIC, as well as violations of childbearing function and termination of pregnancy in women, pre- and postoperative diagnostics and monitoring the patient's condition, with antiphospholipid syndrome.

Control of the APVT indicator is necessary during heparin therapy and treatment with anticoagulants.

What are normal APTT values ​​for different categories of patients

Normally, this indicator for men and women is 24-40 seconds (in different sources you can see different values ​​​​of the norm, but we have given general boundaries). For infants, the norm of APTT in the blood is slightly higher - 25-43 seconds, for premature babies - more than the norm by 3-5 seconds. However, it should be borne in mind that different laboratories, due to the use of different equipment, may be guided by slightly different values ​​from the classical ones.

Therefore, obtaining an increased result does not always indicate pathology.

In normal women, the aPTT may be lowered during pregnancy or during menstruation. Biochemical research blood is not recommended during menstruation. The value of this indicator of the coagulogram can be affected by the fatty or salty food eaten by the patient on the eve of blood donation for analysis.

It is important to know that an increased or decreased APTT can be "false". In the first case, such a result can happen with a high hematocrit or if blood was taken from a catheter. In the second (when the APTT is below normal) - when squeezing out blood or eating, a hematoma formed when taking material from a vein.

Deviations from the norm: decoding possible values

In order to correctly interpret this or that deviation of activated thromboplastin time, the doctor, as a rule, takes into account several results of caogulogram tests. Indeed, even if the APTT is not increased or decreased, but there are deviations in other blood coagulation tests, this may indicate the presence of health problems.

So, for example, if the value of APTT does not correspond to the norm with satisfactory indicators of TT and PT (hereinafter - thrombin and prothrombin time), there is a lack or inhibition of VIII, IX, XI and XII blood coagulation factors along with a deficiency of the enzyme prekallikrein and high molecular weight kininogen - mediator protein in the interaction of proteolytic enzymes and subendothelial collagen in the active phase of blood coagulation. This picture is usually observed in hemophilia and a lack of von Willebrand coagulation factor, which is responsible for the platelets performing the function of repairing damage in the vessels.

A high blood coagulation result compared to the norm during APTT and PTT tests, along with the norm of fibrinogen and TB, is possible with therapy with indirect anticoagulants, as well as a lack of X, V and II luminosity factors.

A normal APTT and TT when PTT is exceeded are evidence of a deficiency of procovertin (the seventh blood coagulation factor). A sharp decrease in this factor (less than 20%) may be a harbinger of hepatic coma.

Proconvertin plays an important role in the diagnosis of hepatocellular insufficiency and further monitoring of its course.

Longer than normal values ​​of APTT, TT and PTT are typical for patients with deep fibrinogenemia and during therapy with fibrinolysis activators (drugs used as an ambulance to dissolve recently formed blood clots and emboli). If only TV is increased, we are talking about other diagnoses. Prolongation of APTT can often mean severe liver damage and associated a- and hypofibrinogenemia.

Treatment with heparin contributes to the prolongation of APTT in the blood, as well as indicators of TT and PTT. However, the test for APTT is more significant here. To determine sensitivity to heparin therapy, an APTT test is done one hour before drug administration. If the deviation from the norm in this case is more than 2.5 times, then the amount of heparin administered should be reduced due to the patient's high sensitivity to the drug.

Even if other values ​​of the coagulogram parameters are within the normal range, an increase in APTT may indicate the presence of lupus anticoagulant in the blood. In this case, this test should be done according to a special technique.

The APTT index may be lower than the reference value, often observed at the initial stage of acute DIC.

A low result of the blood clotting time usually characterizes hypercoagulability. It occurs when a decrease in APTT and PTT occurs simultaneously, which is an indication for the introduction of heparin 15–25 thousand Da or 4.1–6.1 thousand Da. At the same time, clotting control (APTT test) is performed twice a day. The use of high doses of heparin also requires monitoring of such an indicator as antithrombin III, as well as a more accurate test for factor Xa compared to APTT.

Generally speaking, the rate of APTT in the blood is prolonged when any coagulation factor deviates from the norm value by more than 30%. The norm in the blood test may be violated due to:

• vitamin K deficiency;
• hereditary disorders of the hemostasis system;
• the state of acute leukemia;
• DIC;
• bleeding after delivery;
• improper preparation for analysis.

What are the reasons for the deviation from the norm of the analysis for coagulability

In the vast majority of cases, the problems are hidden in the bowels of your liver. Their main reasons are the frivolous lifestyle of the patient. Apart from the transferred infectious and viral diseases, as well as serious poisoning, then alcohol abuse, addiction to fatty, salty, spicy foods, overeating and overweight significantly correct the work of your hemostasis, outlining by no means bright prospects.

How to prepare for analysis

If you are taking an APTT analysis, then, unlike a set of coagulogram tests, there are no restrictions as such on the diet on the eve of material sampling. The only thing I would like to note is that it is still better to donate blood on an empty stomach. If you are taking treatment with heparin or warfarin, then you need to warn the doctor about this, because at certain intervals a control blood test for APTT should be done to evaluate the effectiveness of therapy.

If you came to donate blood from a vein for APTT, then the material will be taken from a vein. As a rule, this procedure is not painful. Unpleasant sensations may occur except when applying a tourniquet. If you fell into the hands of a professional manipulation sister, then the puncture will go almost unnoticed.

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Content

Activated partial thromboplastin time is considered the baseline of the coagulogram, which is aimed at evaluating the effectiveness of the internal coagulation pathway. This INR value is considered important for screening the hemostasis system and may be referred to as APTT (activated partial thromboplastin time).

What is APTT in a biochemical blood test

Medical research on the study of hemostasis attaches importance APTT in biochemical analysis blood. According to this indicator, it is possible to determine the correctness of coagulation processes, the level of fibrinolysis and assess the severity of the disease, choose the right treatment. If the surgeon performs an abdominal or endoscopic surgery, then it almost always has risks of complications - thrombosis, bleeding. To reduce them, the activated partial thromboplastin time is determined.

APTT - not everyone knows what it is, but this value can be found under other names - APTT or cephalin-kaolin time. The study is carried out in conjunction with the determination of PTT (prothrombin time), which differs in the determination of the external activation pathway, and not the internal one. According to these indications, an assessment of the deficiency of blood coagulation factors is carried out.

An APTT analysis is prescribed in the following cases:

• for the diagnosis of hemostasis disorders;
• during pregnancy, diagnosis of infertility;
• at risk of bleeding, thromboembolism;
• preoperative examination;
• coagulation pathology (decrease, increase);
• calculation of the dose of heparins for screening treatment;
• diagnosis of DIC, hemophilia, APS, when phospholipids are impaired.

Blood test for APTT

Many specialists prescribe a coagulogram or an APTT blood test to check the clotting function, the reverse process, and the level of fibrinolysis. The determination is made in the morning on an empty stomach, the day before it, alcohol intake, fatty foods, and drugs that affect coagulation should be excluded. The doctor takes a blood sample from a vein and sends it to be tested for interaction with special reagents.

APTT blood test - transcript

After receiving the taken material, the APTT is decoded, a time indicator is obtained in seconds, which is compared with the norm. To do this, plasma is obtained from the sample, platelets are removed from it, and it is exposed to the activator kaolin, cephalin, and calcium chloride. What is APTT in a blood test, the attending physician will tell. If the level is low, then hypercoagulability is observed. At elevated level and hypocoagulation, there is an increase in the duration of clot formation, which can affect the course of certain diseases and the formation of pathologies.

APTT - the norm in the blood

The rate of APTT in the blood depends on the content of plasma factors. It shows the temporary nature of the formation blood clot in seconds. A variety of sources and doctors may consider normal readings in different ways, each of them has its own reference parameters for coagulograms. The majority adhere normal 24-35 seconds, it is possible to lower it when reading up to 19 seconds, and to increase it - over 40.

APTT above normal - what does it mean

When an increase in aPTT is detected on a coagulological study, it is worth studying this in detail. High concentration indicates hypersensitivity to the drug and requires dose adjustment. If you increase the activated partial thromboplastin time, you can talk about:

• deficiency of clotting factors;
• hemophilia;
• treatment with intravenous heparin;
• lack of vitamin K;
• DIC and antiphospholipid syndromes.

Increase the rate can cause the risk of bleeding. If there were violations during the storage of the sample, its contamination or insufficient amount of material was taken, then the activated partial thromboplastin time is also increased. A technical error that contributes to the increase is the wrong amount of anticoagulant reagent in the test tube.

APTT below normal - what does it mean

The increased risk of pathology of thrombosis or thromboembolism is affected by the factor if the APTT is lowered according to the results of the study. Lower activated partial thromboplastin time can:

• pregnancy, taking oral contraceptives;
• error during venipuncture - tissue injury;
• the first stage of DIC;
• intestinal infarction, myocardial infarction, kidney infarction, pulmonary embolism;
• thrombosis in the legs, vessels of the placenta.

Activated partial thromboplastin time or APTT is medical test with a whole complex of reactions that mimics blood clotting (hemostasis) along the internal pathway. Such an analysis is aimed at assessing the presence of plasma factors, anticoagulants and inhibitors. The study shows the effectiveness of internal blood coagulation, helps to identify hemophilia, monitor patients undergoing gerudin and heparin treatment.

APTT norm indicator

In a biochemical blood test, the APTT norm for an adult ranges from 21 seconds to 35. A prolongation of the APTT means that clotting is slow. This occurs when there are no necessary factors in the blood or substances are present in the plasma that slow down coagulation. A shortening of the APTT below normal indicates that hypercoagulability predominates. When passing the analysis, you should be aware that different laboratory equipment has its own standards. When a result is issued, the standard is indicated in the line "reference values".

What is APTT?

APVT - the period of time for which a blood clot occurs. The process occurs after the addition of calcium chloride or any other reagents containing an activator to the plasma. To date, the coagulogram is the most accurate indicator of diseases that are associated with blood clotting. The main indicators for the purpose of the study:

• deficiency of clotting factors along the intrinsic pathway;
• observation during anticoagulant therapy;
• DIC;
• general assessment of blood coagulability;
• disclosure of the causes of bleeding and thrombosis;
• diagnosis of hemophilia.

In addition, doctors recommend taking APTT control before a planned operation for the timely detection of abnormalities in normal blood clotting in order to avoid complications later. If the APTT is too high, then this indicates a patient's tendency to bleed. The reason for this condition can be caused by:

• severe liver disease;
• vitamin K deficiency;
• lupus erythematosus;
• hemophilia;
• hereditary deficiency of clotting factors;
• antiphospholipid syndrome;
• the second stage of the ICE.

ATTENTION! In order for the analysis to be accurate, it is not recommended to take it to women during menstruation. A decrease in APTT indicates a person's tendency to thrombosis, thrombosis of various origins, or a hereditary factor. Another reason for the shortening of APTT is the first stage of DIC.

Study Description

The method of delivery of the analysis consists in such medical manipulations:

1. A venous blood sample is taken. In the test tube, which is in operation, there is sodium citrate. sodium salt able to bind together calcium ions, which are responsible for clotting.
2. After blood is added to the test tube, other reagents (cephalin or koalin) are added to activate the internal pathway of plasma proteins.
3. Next, calcium chloride is added to the test tube to neutralize the effect of sodium citrate. This allows you to restore hemostasis and evaluate the rate of blood clot formation.

Study preparation

Before testing for cephalin-kaolin time, certain recommendations must be followed. General mode of preparation for the delivery of the analysis:

• It is recommended to donate blood in the morning (8-11 am). Between meals should be at least 8 hours. Water is allowed to be consumed normally. The day before, you need to limit the intake of fatty foods. For emergency studies, tests are allowed 4-6 hours after eating. Glucose tolerance analysis is performed after 12-16 hours of fasting.
• Within 24 hours, alcohol, medication and physical activity should be completely excluded.
• 2 hours before blood sampling, it is advisable not to drink juices, coffee, tea. You should also refrain from smoking, emotional arousal and physical stress. 15 minutes before the test, you should completely calm down.
• It is highly undesirable to donate blood after any physiotherapeutic and medical procedures.
• When re-examination, it is recommended to donate blood in the same laboratory, at the same time of day. To assess the effectiveness of the prescribed treatment, the analysis should be taken no earlier than a week after the last dose of the drug.

What is it used for and when is it prescribed

As mentioned above, an APTT test is performed to diagnose hemophilia and identify the causes of bleeding. In addition, the analysis is prescribed in order to study bruising of unknown origin, disseminated intravascular coagulation, thromboembolism, so that there is no formation of blood clots in the vessels or bleeding. During the preoperative examination, the indications of the coagulogram are important to the doctor if early bleeding is indicated in the clinical history of the patient. The analysis is also prescribed during the treatment of myocardial infarction.

Deciphering the results

The standard coagulogram includes a large number of indicators, so it can not be called cheap in price. Decoding is carried out by qualified doctors of the Invitro company and other leading clinics, analyzing all the parameters in aggregate. Main characteristics:

1. Clotting time. This is the time interval studied from the time when the blood began to ooze from the wound until the moment when it turned into a clot. The norm of the interval for capillary blood is from 30 seconds to 5 minutes, for venous blood - up to 10 minutes.
2. PTI (prothrombin index). Coagulation time ratio of control blood healthy person to the hemostasis of the patient from whom the fence is taken. The indicator characterizes the state of the patient's liver. During pregnancy, it may increase - this is the norm.
3. The concentration of fibrinogen in the blood. The norm is 5.9 µmol / l - 11.7. If the indicator is lowered, then this indicates liver disease. An increased result means a lack of hormones, infection or the risk of developing a malignant tumor.

What affects the results of the analysis

The test results may change if the volume of blood and anticoagulant taken in the tube does not correspond to the 9:1 norm. An increase in APTT may cause high hematocrit or heparin contamination of the sample. On the wrong definition indicators can be affected by a violation of the regimen: smoking and eating fatty foods on the eve of the examination, as well as menstruation or pregnancy.

Causes of increased or decreased APTT

An elevated APTT concentration may indicate serious liver pathology or indicate the presence of specific inhibitors or lupus anticoagulant. If the coagulation assessment reveals low level hemostasis, this indicator can lead to hemophilia or antiphospholipid syndrome. Such a deviation is sometimes associated with symptoms of intravascular coagulation syndrome I degree.

APTT above normal - what does it mean?

There are many reasons for prolongation of thromboplastin time. What does APTT above normal mean?

• von Willebrand's disease;
• hemophilia A and B;
• lack of vitamin K;
• deficiency of kinin and prekalikrein (congenital);
• the introduction of streptokinase or heparin;
• chronic glomerulonephritis;
• taking anticoagulants;
• connective tissue diseases.

APTT below normal - what does it mean?

The predominance of hypercoagulation is also caused by several specific reasons. What does it mean if the indicators in the APTT analysis are below normal:

• increased levels of the blood clotting system or factor VIII;
• resistance to activated protein C factor V;
• hypercoagulation phase of DIC;
• tendency to thromboembolism;
• a normal pregnancy.

How the blood will clot during the study is very important to establish the patient's condition. The results of the analysis will help to evaluate the work of hemostasis in the body and identify many diseases in time. The sooner a deviation from the norm is detected, the faster a person will cope with his illness.