Activated partial thromboplastin time

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Activated partial thromboplastin time( APTT) is a special medical test that mimics the process of blood coagulation along the internal pathway, aimed at assessing the presence of plasma factors, inhibitors and anticoagulants in the blood.

It shows the effectiveness of the internal mechanism of blood coagulability, allows to diagnose hemophilia and monitor patients undergoing heparin and herdin therapy.

Norma APTTV

For an adult, the norm of APTTV is from 21 to 35 seconds. Elongation of APTTV means that the blood is curled more slowly than necessary. This happens in those cases when there are not enough clotting factors in the blood, or there are substances in the plasma that slow blood coagulation.

It should be remembered that different equipment in the laboratory has its own specific norms. When you receive a result, this indicator will be indicated in the column "reference values".

APTTV - what is it?

ACHVT is the time period for which a blood clot appears, this occurs after calcium chloride or other reagents are added to the plasma. At the moment, the analysis is the most accurate indicator, the presence of diseases associated with blood clotting

The basic indications for the appointment ASHVT :

1. Diagnosis of hemophilia;
2. General evaluation of the blood clotting system( revealing the causes of thrombosis and bleeding;
3. DIC( syndrome of disseminated intravascular coagulation);
4. Monitoring of anticoagulant therapy( heparin treatment)
5. Detection of the deficiency of coagulation factors along the internal pathway: II, V, VIII, IX, X, XI, XII

Normally, the fibrin clot is formed within 21-35 seconds. The procedure is based on the following manipulations of :

1. Venous blood is taken into a tube containing sodium citrate towhich has the ability to bind calcium ions responsible for clotting of the blood
2. After that, reagents are added to the tube that activate the internal way of blood coagulation. As the reagents, the most often used are the coalin or kefalin
3. The next step in the study is the addition of calcium chloride to the tube, forneutralizing the anticoagulant effect of sodium citrate and restoring hemostasis, and evaluating the rate of clot formation.

Before the study should adhere to such recommendations as a temporary refusal to take anticoagulant drugs, hunger for 12 hours before the analysis and, if possible, refusal to smoke during the day.

Reasons for increased or decreased APTT

If the APTTV exceeds the norm, this indicates that the patient has possible liver disease or a lack of vitamin K in the body, and this can also indicate the presence of a vocal anticoagulant in the blood.

If the indicators are below normal, then this may be due to a decrease in blood clotting, the presence of hemophilia and antiphospholipid syndrome. In addition, this deviation from the norm may be associated with intravascular coagulation syndrome. A low APTT is a symptom of intravascular coagulation, if there is a deviation, then the patient has grade I disease.

APTTV is above normal - what does it mean?

Causes leading to lengthening above the norm of activated partial thromboplastin time( APTT):

1. Hemophilia A and B;
2. Von Willebrand disease;
3. Congenital deficiency of precalicrein and cinnamine;
4. Introduction of heparin or streptokinase;
5. Condition after a large blood transfusion;
6. Presence of lupus anticoagulant in the blood;
7. Antiphospholipid syndrome;
8. Chronic glomerulonephritis;
9. Systemic lupus erythematosus;
10. Reception of anticoagulants( Warfarin, Sinkumarin, etc.);
11. Vitamin K deficiency;
12. Low fibrinogen in the blood;
13. Liver diseases;
14. II and III phases of DIC syndrome;
15. Coagulation factor deficiency( II, V, VII, VIII, IX, X, XI, XII);
16. Diseases of connective tissue.

As a rule, high results of APTT analysis indicate an increased risk of bleeding due to congenital or acquired deficiency of one or more coagulation factors.

APTTV is below normal - what does it mean?

Shortening of the APTT below normal indicates the predominance of hypercoagulation and can be caused by the following reasons:

1. Activation of the internal coagulation mechanism in thrombosis, thromboembolism. This may be due to the resistance of factor V to activated protein C, an increased level of factor VIII or activated clotting factors.
2. With DIC-syndrome( hypercoagulation phase).
3. Possible with a normally occurring pregnancy.

Decrease in APTT indicates a tendency to thromboembolism.

What affects the results of the

analysis How does the decryption occur? What specifically affects the result of this analysis?

1. Blood test contaminated with heparin.
2. A sufficiently high hematocrit is able to extend the APTTV.
3. The amount of blood that was taken for this analysis. The required ratio of blood taken and anticoagulant in the existing test tube is 9: 1.
4. Folding of blood when it leads to the consumption of all possible clotting factors, and also significantly changes the tolerance of APTT.
5. Many factors also affect such factors as fatty foods, smoking, menstruation cycle and pregnancy in women. These factors can lead to falsely decreased APTT values.

The APTT value is very important for establishing an accurate picture of the patient's condition, especially during pregnancy. The results of the analysis allow not only to evaluate the work of the coagulation system, but also to reveal the presence of certain diseases. And the sooner a deviation of APTT from normal is detected, the easier and faster it is to cope with the disease.