ACTIVATED PARTIAL THROMBOPLASTIN TIME- aPTT

500 Rs

MRP

Discounted Price:

350 Rs

Pre-test preparation or requirements

• Sample can be drawn at any time. No fasting or special preparation required.
• Sample should taken in Citrated vial. Sample should be immediately centrifuged and transfer plasma to aliquot.

Normal range

26- 42 second

Significance of test

1) Activated partial thromboplastin time (aPTT or APTT) is a performance indicator measuring the efficacy of both the "intrinsic" (now referred to as the contact activation pathway) and the common coagulation pathways.
2) Apart from detecting abnormalities in blood clotting, it is also used to monitor the treatment effects with heparin, a major anticoagulant.
3) It is used in conjunction with the prothrombin time (PT) which measures the extrinsic pathway. The test is termed "partial" due to the absence of tissue factor from the reaction mixture. The concept of separate intrinsic and extrinsic pathways of coagulation is useful for understanding and diagnosing blood coagulation abnormalities in vitro, however it should be appreciated that in vivo there are multiple interactions between the two pathways.
4) The APTT will generally be prolonged when a clotting factor level is less than 30-40%. Since the normal range for most clotting factors is 50-150%, a normal APTT does not rule out the possibility of a mild factor deficiency.
5) The common acquired coagulopathies such as liver disease, moderate to severe vitamin K deficiency, DIC and massive transfusion may cause prolongation of the APTT; however the PT will also be prolonged in these disorders, due to multiple clotting factor deficiencies.

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