Glucose, Fasting

This test can be ordered as the fasting time point in the 2-hour oral glucose tolerance test recommended by the ADA for non-OB patients or as a stand-alone fasting glucose. For the 2-h glucose tolerance test, a fasting specimen should be drawn and sent for GLUF; then the patient should drink 75 g glucola, and after two hours have a specimen drawn and sent for GLUPP2. A fasting blood glucose concentration equal to or greater than 126 mg/dL is consistent with a diagnosis of diabetes. Diabetes Care 2016 39: S13-S22

Spectrophotometric

Effective date: 03/01/2015

Upper limit is based on ADA guidelines for diagnosis of diabetes using a fasting glucose measurement. See above for website.

HMC, UW-MT, and UW-NW Onsite Locations:
Preferred: 4 mL blood in LIME GREEN PST tube
Also Acceptable: 4 mL blood in ORANGE RST, GOLD SST, RED TOP, GREEN TOP or GREY TOP tube
Pediatric: 1 Full LIME GREEN MICROTAINER

Offsite Clinic or Other Locations:
Preferred: 4 mL blood in GOLD SST tube
Also Acceptable: 4 mL blood in ORANGE RST, LIME GREEN PST, RED TOP, GREEN TOP or GREY TOP tube
Pediatric: 1 Full LIME GREEN MICROTAINER

Refrigerate plasma/serum

Note: Plasma or serum collected in green, gold or red top tubes should be separated from the cells within 1 hr. and stored refrigerated. Glucose in such specimens is stable up to 16 hr. after collection. Glucose specimens collected in gray top tubes are stable up to 24 hr. without separation or refrigeration.