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Test Code PRO PROTHROMBIN TIME (PT WITH INR)

Important Note

Test subject to Medicare National Coverage Determination (NCD).

See Medical Necessity documentation requirements by clicking on  

Medicare National Coverage Determinations under General Information

to left of this screen.

Additional Codes

LAB320

Performing Location

Porter Hospital Laboratory

Specimen Requirements

Review Collecting a Coagulation Test for complete instructions before drawing specimen.

Specimen Type: Whole blood
Container/Tube: Light-blue top (citrate)

Specimen Volume: 1 full tube

Specimen Minimum Volume: 2.7 mL

Collection Instructions: 

  1. Tubes must be filled to indicator line.

  2. Send specimen in original tubes at room temperature.

  3. Sample stable 24 hours at room temp.  DO NOT REFRIGERATE

 

Specimen Transport Temperature

Room Temperature

DO NOT REFRIGERATE

Test Classification and CPT Coding

85610

Test Schedule / Analytical Time / Test Priority / Turn Around Time

Daily / 24 Hours / Available STAT / Routine - 4 Hours

                                                      STAT - 60 Minutes

Methodology

Photo-optical clot detection

Normal Reference Values

SEC: 9.0-12.3;     INR: 0.8-1.2     Moderate Intensity Coumadin INR = 2.0-3.0.


Adjustments in anticoagulant therapy dose should be based upon the INR and not the PT in seconds. The INR is used only on patients on stable oral anticoagulant therapy. It makes no significant contribution to the diagnosis or treatment of patients whose PT is prolonged for other reasons.

Critical Values

INR >4.0