Patient must be fasting 8-16 hours. Five specimens total; One 7.5 mL serum separator tube (SST), one 5 mL red top tube, or one 4 mL lavender top tube for each draw: Fasting, 30 minutes, 1 hour, 2 hour, and 3 hour. Glucola dose is 75 grams.
Handling:
Allow to clot, centrifuge and immediately separate serum or plasma from cells. Refrigerate. Clearly indicate on each specimen the draw time and fasting or post-glucola dose, and order of each draw, e.g., “1 of 5,” etc. Freeze if specimens cannot be assayed within 24 hours. Avoid repeated freeze/thaw cycles. If multiple tests are ordered, send separate specimens for this test.
Stability:
8 hours ambient, 24 hours refrigerated, or 30 days frozen at -20o C.
Standard Volume:
0.5 mL serum or plasma from each collection.
Minimum Volume:
250 µL serum or plasma from each collection.
Transport:
Refrigerated; or if frozen, on dry ice.
Comments:
Includes fasting, 30 minute, 1 hour, 2 hour and 3 hour insulin levels drawn after a 75 gram oral glucose loading. Patient should be on a regular diet of >150 grams carbohydrate per day for 72 hours before testing.
Rejection Criteria:
Any hemolysis; plasma other than EDTA; specimens frozen and thawed more than once.