Specimen Requirements

1. Draw blood in a blue-top (citrate) tube(s). Send specimen to laboratory within 8 hours at ambient temperature.
2. If specimen is to be stored longer than 8 hours spin down, remove plasma, spin plasma again, and place 1 mL of citrate platelet-poor plasma in plastic vial. (Glass vial is not acceptable.)

Note:  Double-centrifuged specimen is critical for accurate results as platelet contamination may cause spurious results.
3. Freeze specimen immediately at ≤-40° C, if possible.
4. Send specimen frozen.
Note:  1. Each coagulation assay requested should have its own vial.
2. If the patient is being treated with Coumadin®, this should be noted. Coumadin® will lower protein C.
3. Heparin >2 U/mL may interfere with this assay.
4. Lipemic specimen may be rejected.