Collect a Green Top (lithium heparin). Allow specimen to clot completely at room temperature. Centrifuge within 30 minutes of collection.

After separation from cells, specimen is stable for 2 hours at room temperature, 24 hours at 2-8° C, and 6 months when frozen at ≤ -20° C.

If collectiton is Outpatient, spin down and send specimen refridgerated.