Specimen Requirements

Specimen must arrive and be tested within 4 hours of draw.

Specimen Type: Whole blood
Container/Tube: Blue top (3.2% sodium citrate)

Specimen Volume: Full tube

Collection Instructions:

1. Immediately after draw, invert tubes several times to mix blood with additive.

2. Send specimen in original tube.

3. If there is a delay in transport of >4 hours, specimen must be double-centrifuged to prepare a platelet-free plasma specimen as follows:

a. Immediately centrifuge at 3,200 rpm for 15 minutes.

b. Carefully remove plasma from cells avoiding platelet/buffy coat, and transfer plasma into a plastic tube.

c. Centrifuge plastic tube at 3,200 rpm for 15 minutes.

d. Carefully remove top portion of plasma and transfer plasma into a plastic tube leaving approximately 250 mL in bottom to discard.

e. Double-centrifuged plasma should be aliquoted (0.5 mL-1 mL each) into clearly labeled plastic tubes. (Glass vial is not acceptable.)

Note: Number of tests ordered will determine number of aliquots needed, generally 1 aliquot per test.

f. Specimens should be frozen at <-40° C, if possible, and sent together in same container with at least 5 lbs of dry ice. Specimens must arrive in a frozen state.

Additional Information:

1. Double-centrifuged specimen is critical for accurate results as platelet contamination may cause spurious results.

2. Heparin treatment may lower plasma antithrombin.