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Test Code PT Protime (PT), Plasma

Additional Codes

Ordering Mnemonic


Photo-Optical Clot Detection

Useful for monitoring Coumadin® therapy.

Includes International Normalized Ratio (INR).

Performing Laboratory

Holland Hospital Laboratory Services

Specimen Requirements

Specimen must be processed within 24 hours of draw.


Collection Container/Tube: Light blue-top (sodium citrate) tube-Clotted blood is not acceptable.

Specimen Volume: Full tube of blood

Collection Instructions: Invert 6 times to mix blood. Centrifuge and separate plasma within 24 hours of draw. Send specimen in plastic vial.

Specimen Transport Temperature

Ambient up to 24 hours

Specimen Stability Information

Temperature Time
Ambient 24 hours


Day(s) Test Set Up

Monday through Sunday

Available STAT

Test Classification and CPT Coding


Reference Values


9.0-12.5 seconds


Critical value (automatic call-back): ≥5.0