Additional Specimen Instructions

This orderable profile follows the American College of Obstetricians and Gynecologists criteria for the diagnosis of gestational diabetes. This profile includes measurement of a fasting glucose as well as plasma glucose at 1, 2, and 3 hours post 100 gram oral glucose load.

1.The patient should be fasting (8 to 12 hours) prior to beginning this test. 2.Draw a gray top tube for a fasting plasma glucose concentration. 3.Give the patient the 100 gram glucose drink (can be obtained from the laboratory) and instruct the patient to drink the entire volume. 4.Begin timing once the patient has finished the drink. 5.Draw additional gray top tubes 1, 2 and 3 hours after the patient has finished the drink. Gray top tubes are preferred for glucose measurement as they contain a glycolytic inhibitor (NaF) that stabilizes the plasma glucose concentration. If the GTT is drawn in conjunction with other plasma chemistry tests a green top plasma separator tube (LiHeparin) is acceptable if the green top tube is centrifuged within 1 hour of collection. All specimens should be collected in the same container type for the duration of the tolerance.