Collect SST/1.0 mL serum, after 30 minutes of clotting, promptly centrifuge and send.

Alternate collection:
Collect red top, allow to clot for 60 minutes at room temperature, centrifuge, transfer 1.0 mL serum to a screw top plastic vial, indicate sample type on tube and send.

Collect light blue top sodium citrate, tube must be filled. The sample should be mixed immediately by gentle inversion at least six times to ensure adequate mixing of the anticoagulant with the blood. Centrifuge and transfer 1.0 mL to a screw top plastic vial, indicate plasma from light blue on the transport tube.