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2 Hour, 75 gram Glucose Tolerance Test, Pregnancy

Item Value
Approval req'd? No
Available Stat? No
Utilization Guidelines See Additional Information.
Test code OGTP2. GT60 & GT120
Test group Glucose
Performed by Parnassus, Mission Bay & Mt. Zion Chemistry
In House Availability Test available 24 hours per day 7 days per week
Method Oxygen consumption (O2 electrode with glucose oxidase)
Patient Preparation The patient should be instructed by the care-giver to eat a normal diet containing at least 150 g of carbohydrate per day and carry out normal physical activity for at least 3 days prior to the morning of the test. An 8-10 hour fast is required before initial baseline sample collection.
Collection Instructions Outpatient testing at ACC available 0730-1400 weekdays, Mission Bay from 0700-1400 and at 2330 Post St. 0800-1400 weekdays.

The patient should be seated for the test and should not smoke.

Collect all samples in Gray top tubes

Obtain a fasting sample and send to lab for stat glucose testing. The glucose load should not be given and the test aborted if the fasting glucose value is ≥ 92 mg/dL (in accordance with the recommendations of the UCSF Diabetes and Pregnancy program and the IADPSG guidelines). If the test is aborted due to an elevated fasting glucose, refer the patient back to the Diabetes Clinic.
Container type Gray top
Amount to Collect 1 mL blood Click here for Microdetermination info
Sample type Serum
Preferred volume 0.5 mL serum
Min. Volume 0.2 mL serum Click here for Microdetermination info
Units mg/dL
Normal range
Fasting 70-91 mg/dL
1 hour (post glucose) < 180 mg/dL
2 hour (post glucose) < 153 mg/dL
Synonyms Diabetes mellitus
Stability Room temperature 8 hours, refrigerated 2 days
Additional information This glucose tolerance test is the one step procedure generally being implemented at UCSF to screen pregnant patients for gestational diabetes (GDM).

The previous two step procedure which involved a "1 hour 50 gram Glucose loading screen" followed if necessary by a "3 hour 100 gram Glucose Tolerance Test, Pregnancy" has been generally discontinued. However, the "1 hour 50 gram Glucose loading screen" will remain orderable in the event that the clinician decides to request a "1 hour 50 gram Glucose loading screen" in a patient who declines the "2 Hour, 75 gram Glucose Tolerance Test, Pregnancy."

For further information on the "2 Hour, 75 gram Glucose Tolerance Test, Pregnancy," refer to the UpToDate section on screening and diagnosis of diabetes mellitus during pregnancy and also the International Association of Diabetes and Pregnancy Study Groups Recommendations on the Diagnosis and Classification of Hyperglycemia in Pregnancy, Diabetes Care,
33:676-682, 2010
CPT coding 82947
Last Updated 6/1/2017 3:29:17 PM
Entry Number 1608
Lab Procedure Link Click here for Procedure
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