One 7.5 mL serum separator tube (SST). Also acceptable: One 4 mL green top tube (heparin) or one 4.5 mL light green plasma separator tube (PST). Preferred specimen is from patient fasting 8-12 hours; non-fasting specimen is acceptable. Do not draw from a limb receiving an intravenous insfusion. Patient should avoid exercising forearm before collection, which can cause an increase in potassium level.
Centrifuge SST or PST within 2 hours of collection and transport in original tube. Centrifuge green top tube within 2 hours of collection and separate plasma into a plastic tube for transport. Refrigerate.
6 days refrigerated.
2 mL serum or plasma.
1 mL serum or plasma.
Gross hemolysis; specimen left in contact with cells for more than 3 hours; tubes other than those specified.