Patient must be fasting 8-16 hours. Eight specimens total; one 7.5 mL serum separator tube (SST), one 5 mL red top tube, or one 4 mL lavender top tube (EDTA) for each draw. Fasting, 30 minutes, 1-hour, 2-hour, 3-hour, 4-hour, 5-hour, and 6-hour. Glucola dose is 75 grams.
Handling:
Allow to clot, centrifuge, and separate serum or plasma from cells within 2 hours. Refrigerate. Clearly indicate on each specimen the draw time and fasting or post-glucola dose, and order of each draw, e.g., “1 of 8,” etc. Freeze if specimens cannot be assayed within 24 hours. Allow no more than one freeze/thaw cycle. If multiple tests are ordered, send separate specimens for this test.
Stability:
8 hours ambient, 24 hours refrigerated, or 1 months frozen at -20o C.
Standard Volume:
0.5 mL serum or plasma.
Minimum Volume:
250 µL serum or plasma.
Transport:
Refrigerated, or frozen on dry ice.
Comments:
Includes fasting, 30-minute, 1-hour, 2-hour, 3-hour, 4-hour, 5-hour, and 6-hour insulin levels drawn after a 75 gram oral glucose loading. Patient should be on a regular diet of >150 gram carbohydrate per day for 72 hours before testing.
Rejection Criteria:
Hemolysis; plasma other than EDTA; specimen frozen and thawed more than once.