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Test Code PT Prothrombin Time (PT) and International Normalized Ratio (INR), Plasma

Methodology

Turbidometric

Performing Laboratory

Aspen Valley Hospital

Physician Office Specimen Requirements

Container/Tube:  Light blue-top (sodium citrate) tube(s)

Specimen:  1 mL of sodium citrate plasma

Transport Temperature:  Ambient

Collection Instructions:  If there is a delay in transport of >4 hours, spin down and send 1 mL of platelet-poor plasma frozen in plastic vial.

Reference Values

PROTIME

Patients not taking anticoagulants:  11.2-15.5 seconds

INR

Therapeutic ranges for oral anticoagulation therapy: 

In the typical case of venous thrombosis, the target INR is 2.0-3.0. The optimal target range is not the same for all indications. Universal agreement has not been reached on the optimal range for the various indications. For in-depth recommendations and an extensive review see “Chest,” 2008; 133:  no. 6 suppl:  71S-109S.

Critical value (automatic call-back):  ≥5.0 (INR)

Day(s) Test Set Up

Monday through Sunday

Test Classification and CPT Coding

85610