Complete coagulation (APTT, PT, INR, fibrinogen)

Coagulation tests:

Activated partial thromboplastin time (aPTT)

The study of aPTT is a functional test that provides important information about the functioning of the coagulation system and certain factors.

This indicator is most commonly used to control and monitor therapy with non-fractional heparin and thrombin inhibitors (hirudin, argatroban). However, aPTT is not a first-line indicator when evaluating heparin treatment.

The test is also used to diagnose congenital or acquired insufficiency of certain coagulation factors (XII, XI, IX, VIII, VII) in case of suspected hemophilia or von Willebrand disease.

The aPTT test is used to detect the presence of specific or nonspecific coagulation inhibitors in the body - for example, lupus anticoagulant and antiphospholipid antibodies that are associated with clinical manifestations such as thrombosis.

It is also used as an indicator to assess the risk of bleeding before surgery.

Prothrombin time (PT)

Prothrombin is a protein synthesized by the liver and is one of the important factors that promotes blood clotting. Normal coagulation requires several types of proteins called coagulation factors. In the process of coagulation they must act properly and in sufficient quantities.

The assay determines the time (in seconds) during which a thrombus-producing protein called thrombin is produced from inactive prothrombin in the blood plasma taken for analysis.

It can detect both hypercoagulation and hypocoagulation.

PT is an important indicator of the condition of the coagulation system. It gives an idea of ​​the activity of the factors involved in the external coagulation pathway (VII, X, V, I, II). Factors VII, X, V, I, II are synthesized in the liver and the process requires the presence of vitamin K.

Prothrombin time is measured in seconds, but can be expressed in different ways: seconds (sec), prothrombin index in percent (%) and INR (International Normalized Ratio).

Prothrombin index - PI

Prothrombin activity in% is determined by analysis.

International Normalized Ratio (INR)

The analysis determines the relationship between prothrombin index (PI) and prothrombin time (PT).

It is comparable between different laboratories and according to its importance the doctor can determine the dose of prescribed anticoagulants and the interval between their reception.

INR is useful only in anticoagulant therapy and is not used to diagnose and treat patients with prolonged prothrombin time for other reasons.

Fibrinogen - Factor I.

Fibrinogen is an important protein in the coagulation cascade. It dissolves in plasma and platelet granules. In the last phase of blood clotting, fibrinogen is converted to an insoluble form - fibrin and participates in the formation of blood clots.

Fibrinogen is produced by the liver in the amount of 1,7 - 5 g per day. In addition to its role in the coagulation cascade, fibrinogen belongs to the group of acute phase proteins whose levels increase in the presence of a systemic response of the body to severe injury (trauma, extensive burns, infection, etc.).

How to prepare for the test?

Blood sampling is required for analysis on empty stomach , Without taking medication for the last 12 hours. The patient should be informed whether he or she is taking medications that affect blood clotting.

If you are taking blood thinners, Consult your doctor In connection with the examination.

If heparin therapy is required to be monitored, test material should be obtained from a non-heparinized source one hour prior to the next heparin administration.