Test Code LAB0208868 Prothrombin Time (PT) with International Normalized Ratio (INR), Plasma

Methodology

Photometric Clot Detection

CentraCare Laboratory Services

Specimen Type: Plasma

Container/Tube: Light-blue top (3.2% sodium citrate)

Specimen Volume: 5 mL

Collection Instructions:

1.Tube must be full.

2. If less than 24 hours until testing, ambient whole blood is preferred.

3. If there is a delay in testing of >24 hours, centrifuge for 10 minutes at 3,000 rpm, freeze plasma immediately at

-20 ⁰ C and send frozen in plastic vial.

Ambient <24 hours

Frozen >24 hours

NORMAL PT

9.4-12.5 seconds
INR (stable oral anticoagulant therapy)
Std Rx: 2.0-3.0
High intensity Rx: 2.5-3.5
Critical value (automatic call-back): INR >4.0

Monday through Sunday

85610