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1- hour 50 gram Glucose Loading Screen

Item Value
Approval req'd? No
Available Stat? No
Test code GLT1
Test group Glucose
Performed by Parnassus, Mission Bay & Mt. Zion Chemistry
In House Availability Test available at ACC 0730-1530 weekdays.
Test available at 2230 Post St. 0800-1400 weekdays.
Method Oxygen consumption (O2 electrode with glucose oxidase)
Collection Instructions Schedule in advance with ACC outpatient phlebotomy, x32736 or Post St. lab 415-885-7531 (Mt. Zion). This screening test may be given at any time of day, without regard to prior meals.
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 1 hour post-50 g po glucose, without regard to whether patient had been fasting: 70 -139 mg/dL
Synonyms Diabetes mellitus; GCT; Glucose challenge test
Stability Room temperature 8 hours, refrigerated 2 days
Additional information This 1 hour glucose loading screen is part of a two step screening approach previously used to screen pregnant patients for gestational diabetes (GDM). When this step was abnormal, it was followed by the second step "3 hour 100 gram Glucose Tolerance Test, Pregnancy."

The two step screening approach has been generally replaced by the one step
approach to screening for GDM, see " 2 Hour, 75 gram Glucose Tolerance Test, Pregnant."

The 3 hour 100 gram Glucose Tolerance Test previously used in the two step approach will be 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 one step approach involving the "2 Hour, 75 gram Glucose Tolerance Test, Pregnancy.
LOINC code 1558-6
Last Updated 7/2/2015 2:31:27 PM
Entry Number 429
Lab Procedure Link Click here for Procedure
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