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EPIC CODE: LAB2491 Glucose Gestational Tolerance Test , 3-Hour


Sunquest: GTGESC


UPH Methodist Hospital
UPH Pekin Hospital
UPH Proctor Hospital


Four timed samples: fasting; 60 min, 120 min, 180 min. post 100 gram glucose load:
Specimen of choice: gold, red or green (lithium heparin)

Clearly label each sample with actual collection time

Other Acceptable Specimen(s)

Gray top (sodium fuoride/potassium oxalate)

Storage/Transport Temperature

Serum or plasma (lithium heparin) at 2-8oC

If gray top collected: transport unspun ambient or2-8°C.

Stability (from collection to initiation)

After seperation from cells (within 2 hours of collection)

Serum or plasma (lithium heparin)

Ambient (room temperature): 8 hours

Refrigerated: 7 days; 72 hours

Frozen (-20o C) Stability: 1 year

Gray top:

Ambient: 24 hours

Refrigerated: 7 days

Frozen (-20o C) Stability: 1 year

Unacceptable Conditions

Reasons for invalid results include emesis & conditions which delay stomach emptying.


Patient should be fasting for at least 8 hours prior to start of test. Oral administration of 100 gram glucose load after fasting specimen is drawn. Patient should remain inactive and receive nothing by mouth (including tobacco) during test period. A small sip of water or ice is permissible. Arrange in advance with Patient Scheduling.

Days Performed

Monday – Saturday


Enzymatic (Hexokinase)

CPT Codes



This test is a follow up for persons who have a fasting glucose between 100 and 125 ng/dL an elevated gestational screen or have other reasons to suspect diabetes mellitus.

Gestational Diabetes Mellitus is indicated if two or more of the following glucose levels are met or exceeded:

Fasting 95 mg/dL

One hour 180 mg/dL

Two hour 155 mg/dL

Three hour 140 mg/dL