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Test Code PT Prothrombin Time

Important Note

Draw 1 tube- Must be completely filled.  If transport to the lab will exceed 24 hours: Immediately centrifuge specimen and aliquot 2 mL of plasma into a separate plastic vial and send specimen frozen.

Performing Laboratory

Memorial Hospital - Automated Procedures Laboratory     304-388-5953
General Hospital Laboratory     304-388-6244
Women and Children Hospital Laboratory     304-388-2385
Teays Valley Hospital Laboratory     304-757-1770
Greenbrier Valley Hospital Laboratory     304-647-3030
Plateau Medical Center Laboratory 304-469-8621
Beckley Cancer Center Laboratory 304-461-2222

Specimen Requirements

Plasma- Light Blue Top, Sodium Citrate

Draw 1 full, tube by “clean” venipuncture (no excessive trauma).

Immediately after draw, invert tubes several times to mix blood with additive.

Specimen Rejection

  • Hemolyzed specimens
  • Marked lipemia
  • Clotted specimens
  • Tubes not filled completely
  • Specimen too old
  • Not stored properly

Storage and Stability

Unspun Room temperature 18-24oC 24 hours
Spun Room temperature 18-24oC 4 hours
Frozen < -20oC 2 weeks

Reference Values

Prothrombin time ranges may vary depending on specific lot number of reagent used in the laboratory.

 

Critical Value: INR > 4.49

 

Interpretation

2.0-3.0 Moderate Intensity 

2.5-3.5 High Intensity

 

Individuals may require higher or lower ranges based on the underlying thrombolytic risk/indication for anticoagulation.

Methodology

Clot detection

Days Test Set Up and Turnaround

Monday through Sunday, Continuously

AM Collection Expected by 9AM same day
Routine Expected within 24 hrs
Stat Expected within 1 hr
Timed Expected results are test dependant

CPT Coding

85610