Laboratory Medicine Program

Glucose challenge test
(GCT, 50g challenge)

Clinical Decription:
The glucose challenge test is used as a screening test for gestational diabetes. This test measures the plasma glucose 1 hour after a 50-g glucose load is given orally and can predict >90% of women with GDM.
<br/><em>Davidson MB. Diabetes Mellitus, 4th ed. Saunders Company, 1998:328-329.</em>

Method: Automated/Manual; Advia

Component Tests Used: n/a

Reference Ranges Used:
Normal glucose 1 h < = 7.8 mmol/L

Specimen Type: grey stoppered tube
Collected In: NaF/K oxalate
Volume: 3 mL (minimum: 1 mL)

Shipping: room temperature or 4C

Special Instructions: For screening for gestational diabetes. Give 50 g oral glucose load at between 24 - 28 weeks gestation, non-fasting. Take blood specimen at 1 hour after ingestion of glucose drink. Patient cannot eat or drink during the test. Centrifuge sample.

Testing Schedule(s): Daily.

Turnaround Time: 1 day

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For more information, call 416.340.5227 or 1.866.865.5227

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