One 7.5 mL serum separator tube (SST). Also acceptable: One 4 mL green top tube (sodium or lithium heparin) or one 4.5 mL plasma separator tube (PST).
Handling:
Centrifuge SST or PST and transport in original tube. Specimen drawn in green top tube must be centrifuged and the plasma separated into a plastic vial for transport. Refrigerate.
Standard Volume:
2 mL serum or plasma.
Minimum Volume:
0.5 mL serum or plasma.
Transport:
Refrigerated.
Comments:
Hemolyzed specimens can cause falsely elevated results because of intracellular magnesium levels.
Rejection Criteria:
Tubes other than those specified; gross hemolysis.