Published on December 19, 2017

Glucose Tolerance Test, 3 hour

Mint Green Plasma Separator Tube

Tube Type

(Includes: Fasting Glucose Performable, 1 hour Glucose Performable, 2 hour Glucose Performable and 3 hour Glucose Performable)

Test ID LAB164
CPT Code(s) 82950 X 4
Group/Individual Test Group
Laboratory Core Laboratory
Tube Station Routine: 30, STAT: 888
Specimen Routine: 3 mL blood/Li Heparin plasma separator tube/Mint Green top. Also acceptable serum (Gold SST / Red Top Tube)
Micro: 200 µL blood/mint green top bullet/gold top/red top
Availability 24 hr/day
Turnaround Time STAT 1 hr; Routine 2 hrs
Reference Range Normal:

Fasting GTT: 70-99 mg/dL

1 Hour Glucose: 40-179 mg/dL

2 Hour Glucose: 40-154 mg/dL

3 Hour Glucose: 40-139 mg/dL

Reference ranges from Carpenter Coustan Criteria, Standards of Medical Care in Diabetes in 2019.

Critical: <40 mg/dL or >400 mg/dL

Panel includes performable tests for fasting, 1 hour, 2 hour and 3 hour glucose. Once order is released and the fasting sample is generated, the 1 hour, 2 hour and 3 hour samples can be collected.

Do not order these tests individually as they are included in the panel.

Reviewed by Christopher Parker on December 07, 2021

Note: Reference ranges provided on this web site are for guidance only, and may not reflect the most recent changes. Refer to laboratory reports for current reference data.

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