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Glucose Tolerance Test, Non-pregnant
|Utilization Guidelines||THIS TEST IS NO LONGER RECOMMENDED FOR ROUTINE USE.
See Additional Information.
|Performed by||Parnassus & 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 and carry out normal physical activity for at least 3 days prior to the morning of the test. An 8-14 hour fast is required before initial baseline sample collection.|
|Collection Instructions||For outpatients, PLEASE SCHEDULE IN ADVANCE with the ACC outpatient lab, 415-353-2736, or Post St. lab, 415-885-7531. Outpatient testing at ACC available 0730-1530 weekdays, and at 2330 Post St. 0800-1400 weekdays.
The patient should be seated for the test and should not smoke.
A gray top tube should be used.
For patients < 18 years of age, obtain the patient's weight and give the patient 1.75 g of glucose per kg of body weight. If the weight is in pounds, divide by 2.2 to get kg. Do not provide more than 75 g dose regardless of body weight.
|Container type||Gray top, Gold top acceptable|
|Amount to Collect||1 mL blood Click here for Microdetermination info|
|Preferred volume||0.5 mL serum|
|Min. Volume||0.2 mL serum Click here for Microdetermination info|
* If confirmed on another day by repeat OGT, or a diagnostic elevation of the fasting or non-fasting glucose.
|Stability||Room temperature 8 hours, refrigerated 2 days|
|Additional information||Based on 75 g dose ingested over 5 minutes.
THIS TEST IS NO LONGER RECOMMENDED FOR ROUTINE USE.
When performed,it is abbreviated to a single 2 hour post-glucose specimen.
All patients should be screened with a fasting glucose: Do not perform this test if the fasting glucose exceeds 125!
90% of patients whose 2 hour level is > 199 mg/dL have fasting hyperglycemia, obviating the need for tolerance testing.
Glucose tolerance beverages are available in 100 g bottles (10 g/fl. oz. at 10 oz.) at ACC, and 100 g and 50 g bottles (10 g/fl. oz., 5 g/fl. oz.both 10 oz.) at Post St.
Reference values from position statement of the American Diabetes Association on Diagnosis and Classification of Diabetes (Diabetes Care, Volume 34, Supplement 1, January 2011).
|Last Updated||9/18/2012 2:34:26 PM|
|Lab Procedure Link||Click here for Procedure|
If you have additional questions regarding this test, please call: 415-353-1667