Laboratory Test Detail

Last Updated: July 22, 2024 @ 9:13 am


Glucose Tolerance, 2 Hr [ADA-GDM]

  • One Gray Top (1HR)
  • One Gray Top (2HR)
  • One Gray Top (FAST)

Also Acceptable:
  • One SST (1HR)
  • One SST (2HR)
  • One SST (FAST)
  • Three 4 mL (Min:1 mL) Whole blood in Gray Top. Submit Refrigerated.

Also Acceptable:
  • Three 1 mL (Min:0.5 mL) Plasma . Submit Refrigerated. Submit in a Standard Transport Tube.
  • Three 1 mL (Min:0.5 mL) Serum in SST. Submit Refrigerated.
Special Handling:
  • ADA Recommends:
    1. Perform at 24-28 weeks gestation in women not previously diagnosed with overt diabetes.
    2. The GTT should be performed in the morning after an overnight fast of at least 8 hours.
    3. Draw fasting specimen, then give 75gm glucola. At 1 hour draw "1 HR" post sample. At 2 hour draw "2 HR" post sample. Label tubes "Fasting", "1 HR", and "2 HR".

    Other alternative samples:
    Green Top (Li Hep), Lavender EDTA, Pink EDTA, Red Top.
    If using alternative serum or plasma separate from cells ASAP.
    Serum or plasma stability: Ambient 8 hrs, RF 3 days, FZ 1 month
Rejection Criteria:
  • Hemolyzed specimens
  • Microbially Contaminated
  • Unlabled Specimens
Stability:Ambient: 1 Day(s); Refrigerated: 3 Day(s); Frozen: Unacceptable; Incubated: Unacceptable
  • Colorimetric
  • Kinetic
Reported:1-3 Day(s)
CPT Codes:
  • 82951
Interpretive Data:Please see report for interpretive data.
  • 2401 - GLUCOSE, 1HR
  • 2402 - GLUCOSE, 2HR
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