One 7.5 mL serum separator tube (SST). Fasting specimen recommended. Also acceptable: One 5 mL red top tube or one 4 mL green top tube (heparin).
Handling:
Allow to clot, centrifuge and separate serum or plasma within 2 hours. Folate is a light-sensitive analyte. Protect the specimen from light. Frozen specimens preferred. Specimens refrigerated up to 24 hours are also acceptable. Freeze if specimen cannot be assayed within 24 hours. If a frozen specimen is submitted, separate tubes must be sent for multiple tests. Allow no more than one freeze/thaw cycle.
Standard Volume:
0.5 mL serum or heparinized plasma.
Minimum Volume:
200 µL serum or heparinized plasma.
Transport:
Refrigerated if received in laboratory within 24 hours of collection, or frozen on dry ice.
Rejection Criteria:
Moderate to gross hemolysis; EDTA specimen; specimen frozen/thawed more than once; refrigerated specimen received in laboratory more than 24 hours after collection.