Specimen Requirements

Draw blood in a light blue-top (3.2% sodium citrate) tube(s), and send 4.5 mL of sodium citrate whole blood. (Clotted or visibly hemolyzed specimen, specimen drawn in wrong tube, or tube that has less than expected fill is not acceptable.)
Note:  1. Mix 9 parts of freshly drawn blood with 1 part of 3.2% sodium citrate anticoagulant. Invert tube gently 3 to 4 times immediately after venipuncture to ensure proper mixing of blood and anticoagulant.
2. If blood is drawn through an indwelling catheter, flush line with 5 mL of saline. Discard first 5 mL of blood or 6 dead space volumes of catheter, or use for other laboratory tests.

3. If blood is drawn with a butterfly set, a waste tube must be drawn to eliminate dead space of tubing to ensure adequate blood is drawn into coagulation tube.

4. 3.2% sodium citrate concentration must be adjusted in patients who have hematocrit values >55%.

5. If testing cannot be performed immediately, spin down, separate and refrigerate plasma in plastic vial. Plasma can be stored up to 72 hours at 4^oC.