APTT is a blood test that assesses the function of the intrinsic and common pathways of the coagulation cascade.

It helps detect bleeding disorders, clotting disorders, and monitor anticoagulant therapy.

Doctors often order APTT along with Prothrombin Time (PT) to get a complete picture of blood clotting ability.

Clinical uses include:

Diagnosing hemophilia and other clotting factor deficiencies.

Monitoring patients receiving heparin therapy.

Investigating unexplained bleeding or abnormal clotting.

The test is simple, safe, and requires a blood sample.

Analyte: Time taken for plasma to clot after adding reagents (measured in seconds).

Normal Range: Typically 25–35 seconds (ranges may vary by lab).

Prolonged APTT: May indicate hemophilia, von Willebrand disease, liver disease, vitamin K deficiency, or anticoagulant therapy.

Shortened APTT: Rare, but may suggest increased risk of clotting.

Clinical Use:

Detects clotting factor deficiencies.

Monitors anticoagulant therapy (especially heparin).

Helps diagnose bleeding disorders.