3 specimens required: One fasting glucose, one fasting insulin, and one 2-hour glucose level post-Glucola dose. Patient must be fasting 8-16 hours. For fasting draws and 2-hour glucose: One 7.5 mL serum separator tube (SST) each draw. Also acceptable: One red top tube each draw.
Centrifuge and separate serum from cells and immediately pour into plastic vials. Refrigerate. Clearly mark tubes as Fasting or 2-hour post-glucose dose. Freeze serum if specimen will not be assayed within 24 hours. Allow no more than one freeze/thaw cycle. If multiple tests are ordered, send separate specimens for this test.
8 hours ambient, 24 hours refrigerated, or 1 month frozen at -20o C.
1 mL serum each fasting insulin, fasting glucose, and 2-hour glucose.
0.5 mL serum each draw.
Refrigerated, or frozen on dry ice.
Test includes fasting insulin, fasting and 2-hour glucose level drawn 2 hours after a 75 gm oral glucose dose. Patient should be on a regular diet of <150 grams of carbohydrates per day for 72 hours before testing. Fasting insulin can be done on serum only. Fasting glucose and 2-hour glucose levels can be done on serum or plasma (one grey top tube with potassium oxalate/sodium fluoride).
Serum separator tube (SST) not spun within 2 hours; more than one freeze/thaw cycle.
MEDICARE MAY REQUIRE A SIGNED ADVANCE BENEFICIARY NOTICE (ABN) FOR THIS TEST