Prothrombin time with INR


Test Code 8847


CPT Code(s) 85610


Methodology Photo-optical Clot Detection


Limitations Expected impact by therapeutic levels (potential interference depends upon drug concentration): Warfarin: prolonged; Heparin (UFH or LMWH): little to no effect (reagent contains a heparin neutralizer); Dabigatran or Argatroban (Thrombin Inhibitors): normal to prolonged; Rivaroxaban or Apixaban (Factor Xa Inhibitors): prolonged.


Reference Range(s)


PT 9.0-11.5 sec




Reference range 0.9-1.1
Moderate – intensity Warfarin therapy 2.0 – 3.0
Higher – intensity Warfarin therapy 3.0-4.0


Clinical Significance Screening test for abnormalities of coagulation factors that are involved in the extrinsic pathway. Also used to monitor effects of Warfarin therapy and to study patients with hereditary and acquired clotting disorders.




Test FAQ


Prothrombin Time with INR


Alternative Name(s) PT


Prothrombin Time with INR Collection Guide


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The CPT codes provided are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the Payor being billed.