Goal: To markedly reduce the platelets in the sample (< 10,000 per µL).
Specimen processing:
(1) Collect the patient's blood sample into tubes containing 3.2% sodium citrate and gently invert several times to mix.
(2) Immediately centrifuge the specimen at 1,500 g for 15 minutes.
(3) When the centrifuge stops, remove the tube. Aspirate the plasma using a plastic (not glass) transfer pipette, being careful to avoid the buffy coat layer.
(4) Place the aspirated plasma into a new plastic tube.
(5) Centrifuge the plastic tube at 1,500 g for 15 minutes.
(6) Aspirate the supernatant with a plastic transfer pipette without disturbing the material at the bottom of the tube.
(7) Place the aspirated plasma into a new tube and seal.
(8) Inspect the tube for fibrin and/or red blood cell clots. If any are present then the specimen must be rejected and a new sample collected.
(9) Freeze the sample immediately at -40°C or lower.
