- Transaction Code: 3200-04
- CPT Code (Suggested): 85610
The prothrombin time (PT) is a kinetic screening test performed by adding a sensitive tissue thromboplastin reagent and calcium chloride to plasma using an automated method. The PT assesses the extrinsic pathway of coagulation that includes factors VII, X, V, prothrombin, and fibrinogen. Prolongation of the PT can be caused by factor deficiency or factor inhibitor. The PT is more sensitive than the APTT for liver disease or the presence or oral anticoagulants. The PT is less sensitive than the PTT to the presence of heparin or a lupus-like inhibitor. Improper sample collection or processing can result in shortening or prolongation of the PT.
- Sample Required: 0.5 ml frozen plasma x4 or (2) 3.2% sodium citrated tubes, 5 ml each.
- See Sample Requirements when ordered with other tests.
- Normal Range: Contact laboratory
- Analytic Time: Within 5 working days
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