Specimen Requirements

Container/Tube Type: 

Light Blue (Citrate) - Two tubes

1. Two (2.7 mL blood in a 3.0 mL) blue top (Na Citrate) tubes or three (1.8mL Na Citrate tube) light blue top. Minimum: One (2.7 mL blood in a 3.0 mL tube). 3.2% buffered sodium citrate is the only acceptable anticoagulant concentration for this testing.
2. Spin down, remove plasma, spin plasma again, and place 1.5 mL of platelet-poor plasma into 2-3 plastic vials. Each vial must contain 1.5 mL. (Glass vial is not acceptable.)
3. Double-centrifuged specimens are critical for accuracy as platelet contamination may cause spurious results.

4. Place into 2-3 separate plastic vials, each containing 1.5 mL of double spun plasma. Minimum 1.5 mL plasma is needed. (.75 mL in 2 vials).
If a PT and/or PTT is ordered, an additional blue top tube or frozen aliquot MUST be submitted.
5. Freeze specimens immediately at ≤ -40° C.

Platelet Poor Plasma
Centrifuge Specimen
Recommended centrifuge speed is 1500 x G for at least 15 minutes. Be careful that the tubes are evenly balanced when placing them into the centrifuge. When the centrifuge stops, carefully remove and rack tubes. Be aware that an unbalanced centrifugation, speed too slow, or centrifugation for too short of a spin time may all lead to an increase number of cells in the plasma which could contribute to a clotted specimen or erroneous results.
Remove Plasma
To remove plasma, start from the top, gently draw specimen into pipette as you go further down tube. Leaving approximately 0.5mL of plasma will insure that you do not disturb the buffy coat and cell layer.
Second Spin
Plasma separated from cells goes back into the centrifuge for a second spin. Balance and centrifuge the tubes. Failure to perform a second spin will result in plasma containing too many platelets which interfere with some coagulation testing and is a contributing factor for a clotted specimen.
Transfer Plasma to Aliquot Tubes
Pipette plasma from second spin tube into labeled aliquot tubes without disturbing the bottom 0.5mL.
Specimen Storage
Promptly freeze specimens after processing.