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Test Code
PTP
Test Name
Prothrombin Time with International Normalized Ratio (INR)
CPT Codes
85610
Included Tests
  • Prothrombin Time
  • International Normalized Ratio (INR)
Expected Turnaround Time
1 day
Clinical Utility
  • Evaluation of the extrinsic coagulation system; aid in screening for congenital and acquired deficiencies of factors II, V, VII, X, and fibrinogen, as well as therapeutic monitoring of warfarin (Coumadin®) anticoagulant therapy.
Specimen and Container Info

Specimen Type: Plasma  

Collection Container: 1 Full Light Blue Top (Sodium Citrate) 

 
Collection Instructions
Blood should be collected in a blue-top tube containing 3.2% buffered sodium citrate. Evacuated collection tubes must be filled to completion to ensure a proper blood-to-anticoagulant ratio.
Processing and Submission Instructions

If testing cannot be completed within 24 hours, create platelet poor plasma according to the Specimen Collection and Processing Guidelines for Coagulation Testing .
Transport Instructions

 Transport to the laboratory at room temperature.
Stability Requirements

Room Temperature

24 hours

Frozen

Platelet poor plasma: 14 days 
Causes for Rejection
  • Clotted specimen
  • Specimen past stability
  • Specimen not properly filled
Methodology
Mechanical Clot Detection
Reference Intervals
  • Prothrombin Time 12.0 - 14.6 seconds
  • Therapeutic Ranges INR:

Ambulatory Surgery: <1.5

Coumadinized Patient (DVT, PE, or A. Fib): 2.0 - 3.0

Mechanical Heart Valve: 2.5 - 3.5
Critical Values

HNL Lab Medicine Critical Values
Performing Location
17th Street Hospital, Carbon Hospital, Cedar Crest Hospital, Cedar Crest Red Lab, Dickson City Hospital, Hazleton Hospital, Hecktown Oaks Hospital, Muhlenberg Hospital, Pocono Hospital, Redeemer Health, Roble Road Core Laboratory, Schuylkill Hospital
Alternate Names
  • Prothrombin Time with INR
  • Protime with INR
  • INR
Testing Schedule
Routine daily, STAT testing available
The American Medical Association (AMA) Current Procedural Terminology (CPT) codes published by HNL Lab Medicine are guidelines and are intended for informational purposes only. CPT coding is the exclusive responsibility of the billing entity. View the Terms.
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