Draw blood in a lavender EDTA tube.  Centrifuge and separate plasma from cells within 6 hours of collection.  Send 2.0 mL plasma (1.0 mL minimum) in a screw-capped plastic vial.  Dedicated specimens are required.  Specimens used in other assays will not be tested.

Rejection criteria:

Serum, heparinized plasma, whole blood, specimens collected using gel-based separation tubes, and specimens submitted to repeated freeze-thaw cycles.