What Is the Partial Thromboplastin Time?

The blood coagulation mechanism is divided into internal and external coagulation systems. Activated partial thromboplastin time (APTT) simulates endogenous coagulation in vivo (including factors , , , , , , , coagulation). Zymogen and fibrinogen), measuring the time required for plasma clotting to reflect whether the endogenous coagulation factor is abnormal, is one of the most commonly used tests to screen endogenous coagulation function.

The blood coagulation mechanism is divided into internal and external coagulation systems. Activated partial thromboplastin time (APTT) simulates endogenous coagulation in vivo (including factors , , , , , , , coagulation). Zymogen and fibrinogen), measuring the time required for plasma coagulation to reflect whether the endogenous coagulation factor is abnormal, is one of the most commonly used tests to screen endogenous coagulation function.

Name

Partial thromboplastin time

category

blood

Partial thromboplastin time reference interval

25.1 35.0s (the reference interval of each detection system varies).

Clinical significance of partial thromboplastin time

APTT is a more sensitive method for detecting the lack of endogenous coagulation factors, and has replaced the ordinary test tube method clotting time (CT) measurement.

(1) Prolonged APTT (the measured value of the subject is longer than the normal control by more than 10s): seen in factor (can detect factor : C less than 25% of mild hemophilia), , , deficiency This test is also extended when severe factors X, V, thrombinogen, fibrinogen deficiency, and anticoagulants are present in the blood circulation. The sensitivity of APTT to detect factors and deficiency is higher than that of factor and F. Hyperlipidemia can pseudo-prolong APTT.

(2) Shortening of APTT: factor VIII and activity increase, DIC hypercoagulable period, thrombotic disease, thrombocytosis, etc. Note: Increased activity of a single factor (such as factor F) can make APTT falsely shorter, and the results can mask the lack of other coagulation factors.

Partial thromboplastin time considerations

Anticoagulated specimens used to determine APTT should be left at room temperature for 4 hours without opening, that is, plasma should be centrifuged; anticoagulated specimens with opened lids should not exceed 1 hour. When separating plasma, be sure to remove platelets.