Specimen Requirements

DO NOT DRAW THROUGH A HEPARINIZED LINE

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%.

Plasma can be stored either on cells or siphoned from the cellular components in a closed tube at room temperature. Plasma can also be separated and frozen at ≤ -18C within 4 hours of collection.

Room Temperature: 15 to 25C (plasma stored on cells) testing must be completed within 4 hours

Room Temperature: 15 to 25C (plasma siphoned from cells) testing must be completed within 4 hours

Specimens frozen at ≤ to -18C (separated) must be tested within 3 days

If the plasma cannot be tested within 4 hours, spin down, remove plasma, and spin again. Double-centrifuged specimen is critical for accurate results as platelet contamination may cause spurious results.  If there is a delay in testing greater than these limits, freeze specimen in plastic vial. A frost-free freezer should not be used because of the freeze/thaw cycles.

Unspun specimens must be transported at ambient temperature and arrive at the laboratory within two hours of draw.