Partial thromboplastin time (PTT)

APTT; PTT; Activated partial thromboplastin time

Partial thromboplastin time (PTT) is a blood test that looks at how long it takes for blood to clot. It can help tell if you have a bleeding problem or if your blood does not clot properly.

A related blood test is prothrombin time (PT).

How the Test is Performed

How to Prepare for the Test

How the Test will Feel

Why the Test is Performed

Normal Results

What Abnormal Results Mean

Risks