Glucose Tolerance 100 G (GT1)

Department: Chemistry
Test Synonym(s): LAB164, GT1, Gestational Diabetes
CPT Codes: 82951, 82952
Methodology: Enzymatic (Hexokinase/G-6-PDH)
Reference Range: Gestational diabetes diagnosed if at least 2 values exceed the following cut-offs: Baseline:<95 mg/dL; 1 hr:<180 mg/dL; 2 hrs:<155 mg/dL, 3 hrs:<140 mg/dL
Tube Type: Grey top - 5 mL, Performed following 100 g Glucola ingestion if screening GTT is abnormal. Overnight fasting is required.
Specimen: Plasma
Pediatric Requirements: 1 light green top microtainer
Volume: 2 mL plasma
Minimum Volume: 1 grey top (Pediactric = 1 light green top microtainer)
Temperature: Separate within one hour and store at 2-8C until delivery
Stability: Refrigerated: 3 days; Frozen: 6 months
Reasons for Rejection: Hemolysis, improper collection
Days Performed: Daily
Times Performed: Continuous
TAT: STAT: 1 hour; ROUTINE: 2 hours after receiving in lab
Significance: Diagnostic of Gestational Diabetes
Special Instructions: Must show collection time. Draw samples at fasting, 60, 120 and 180 minutes post-oral Glucose load. Label tubes as: fasting, 60, 120 and 180 minutes collection, respectively.

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