Normal range: 26-35 seconds
Comment: T screen the integrity of the intrinsic pathway of coagulation (factors VIII, IX, XI, and XII) and to a lesser extent the common pathway (fibrinogen and factors II, V, and X). May detect lupus anticoagulants, but the PTT should not be used to screen for lupus anticoagulants because the PTT may or may not be prolonged (depending on the reagents). Also used to monitor
Sample: Citrated plasma