One 7.5 mL serum separator tube (SST). Also acceptable: One 4 mL green top tube (heparin) or one 4.5 light green plasma separator tube (PST). Patient should fast 8-12 hours. Non-fasting specimen is acceptable. Do not draw from a limb receiving an intravenous infusion. Patient should avoid exercising forearm before collection, which can cause an elevation i potassium level.
Handling:
Allow to clot, centrifuge SST or PST within 2 hours of collection and transport in original tube. Refrigerate. Centrifuge green top tube within 2 hours of collection and separate plasma into a plastic tube for transport. Refrigerate.
Stability:
6 days refrigerated.
Standard Volume:
2 mL serum or plasma
Minimum Volume:
1 mL serum or plasma
Transport:
Refrigerated.
Rejection Criteria:
Gross hemolysis; specimen left in contact with cells more than 3 hours; tubes other than those specified. Frozen specimen should be thawed only once.