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Test Code PTINR Prothrombin Time (PT), Plasma

Important Note

Useful for:

Monitoring of intensity of oral anticoagulant (Coumadin(R)) therapy when combined with INR

Screening assay to detect deficiencies of one or more coagulation factors

Screening assay to detect coagulation inhibition

Performing Laboratory

MaineGeneral Medical Center

Reference Values

INTERNATIONAL NORMALIZED RATIO (INR)

Normal range:   0.8-1.2

Therapeutic range:  2.0-3.0 (standard therapy)

Critical value (automatic call-back):  >4.0

Specimen Requirements

1. Draw a full, light blue-top (3.2% sodium citrate) tube. Invert several times to mix blood.

2. Send sodium citrate whole blood in original VACUTAINER®. Forward unprocessed whole blood promptly.

3. If there is a delay in transport of ≥24 hours, process specimen as follows:

A. Centrifuge specimen for 10 minutes at 3,000 rpm, remove plasma, and place 0.5 mL of sodium citrate plasma in plastic vial. (Glass vial is not acceptable.)

B. Send specimen frozen in plastic vial.

Note:  1. The following specimens will rejected:

A. Clotted or hemolyzed specimen

B. Hematocrit >55%

C. Incorrect anticoagulant

D. Overfilled or underfilled tube

2. Label specimen with patient’s name (first and last), date of birth, date and time of draw, and phlebotomist’s initials.

Day(s) Test Set Up

Monday through Sunday

Test Classification and CPT Coding

85610