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Gestational GTT Confirmation (0-3 HR)

Tube Type

Test ID LAB17001
EPIC ORDER GESTATIONAL GTT CONFIRMATION (0-3 HR)
CPT Code(s) 82951, 82952 
Group/Individual Test Group
Laboratory Core Laboratory
Tube Station Routine 30, STAT 888
Specimen Routine: 3 mL blood/green lithium heparin gel tube/gold SST or red plain tube also acceptable 
Micro: 200 µL blood/green lithium heparin gel microtainer/gold SST microtainer or red plain microtainer also acceptable
Availability Routine: 24 hr/day
Turnaround Time STAT 1 hr; Routine 2 hrs
Reference Range Normal:
Component Reference Range (mg/dL)
Fasting Glucose <95
1-hour Post Glucola <180
2-hour Post Glucola <155
3-hour Post Glucola <140
Critical Values <54 mg/dL or >400 mg/dL
Comments
  • This test is for pregnant individuals after administration of 100 g of Glucola and is step two in the Carpenter Coustan Criteria for screening for gestational diabetes.  This test automatically times the collection of four glucose measurements for fasting glucose, 1-hour Post glucola, 2-hour Post glucola and 3-hour Post glucola.  Do not order the individual components as they are included in the test.
  • Reference Range Source: Carpenter Coustan Criteria (NIH Consensus) for 2 step GDM screening is endorsed American College of Obstetricians and Gynecologists

Reviewed by J. Carr on November 25, 2025

UNC Hospitals
McLendon Clinical Laboratories
101 Manning Drive
Chapel Hill, NC 27514