One 4.5 mL light blue top tube (sodium citrate). Collect by careful venipuncture to avoid tissue fluid contamination or hemolysis. Do not use needles smaller than 23 gauge. Fill tube to maximum draw, at least 90% full. Mix by gentle inversion.
Due to short stability, specimen must either be sent STAT to arrive in laboratory within 4 hours, or send frozen. For STAT, refrigerate and keep capped in original tube. Call for STAT pick-up. For standard delivery, centrifuge to produce platelet-poor plasma and using a plastic pipette, transfer plasma to a plastic tube. Label with patient name, I.D. number, test, and “citrated plasma.” Freeze immediately. Send to the laboratory within 7 days. If multiple tests are ordered, freeze a separate aliquot for this test.
4.5 mL light blue top tube (sodium citrate) or 2 mL plasma.
1.8 mL light blue top tube (sodium citrate) or 0.5 mL plasma.
Original tubes refrigerated if STAT, or citrated plasma frozen on dry ice.