Specimen:

Plasma

Collection Medium:

Minimum:

Full draw; any size blue top(mix well). Tube must be at least 90% full.

Analytic Time:

2 hours (upon receipt in laboratory)

Reference Range:

9-12 seconds

INR Critical Reference Value: greater than 3.9

Comments:

The INR corresponding to the PT is reported to assist in the monitoring 
of oral anticoagulants.  Must be drawn swiftly with a clean 
venipuncture (no hematoma).  Time drawn must be indicated on 
requisition.  Obtain special tube from lab if hematocrit is over 55%.  
Sample should be kept at room temperature, unopened to be delivered to 
lab within 24 hours.

Prothrombin Time may be performed on the same collection tube as 
Activated Partial Thromboplastin time (aPTT) and Fibrinogen.

Please print, complete and submit the Advance Beneficiary Notice 
(ABN) along with the Laboratory Requisition before shipping the 
specimen.

Methodology:

Optical clot detection.

Sample
Processing:

Centrifuge within two hours of draw time.
Aliquot serum/plasma into plastic container and cap (glass is not 
acceptable).
Centrifuge a second time at 3500 RPM for 10 minutes and aliquot into a 
new, labeled plastic tube.

Sample
Storage:

Freeze specimen immediately.

Transport
Instructions:

Place specimen into zip-lock type bag, seal bag.
Place requisition into outside pocket of bag.
Place dry ice on top of specimen in styrofoam container.

CPT Code:

85610

See also:
Activated Partial Thromboplastin Time (aPTT), Plasma

See Additional Information:
Hematology Critical Lab Values
International Normalized Ratio (INR)
Phlebotomy Tubes and Order of Draw