Prothrombin Time (PT)

Prothrombin time (PT), with the INR included as part of the PT, is covered primarily to monitor warfarin therapy, to evaluate patients with signs or symptoms of bleeding or thrombosis, to assess patients with histories of conditions affecting the extrinsic coagulation pathway, and to support pre-thrombolytic therapy evaluation. Coverage is limited by frequency rules (ESRD: more than weekly requires documented medical necessity; stable warfarin patients ordinarily require testing only every 2–3 weeks), by nonutility for heparin-only monitoring, and by the requirement that pre-procedure testing (other than thrombolytic therapy) be supported by signs or personal history of coagulopathy; the INR is not separately payable when reported with PT.

"PT is covered to monitor and guide dosing in patients taking warfarin; the INR calculation is included as part of the PT test."