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Test Code SQ GESGTT, EPIC LAB3966 2 Hour Gestational Tolerance


HexoKinase/Glucose-6-Phosphate Dehydrogenase (G6PDH)/Ultraviolet (UV)

Note: This screen is only for women between the 24th and 28th week of pregnancy.

Performing Laboratory

Meriter Laboratories

Specimen Requirements

Patient Preparation:

1. Patient must be on an unrestricted diet (>150 g carbohydrates) and normal physical activity for at least 3 days prior to testing.

2. Fasting (8 hour).


Performance of Test:

1. Draw blood for a fasting glucose.

2. Give patient a 75 g oral dose of glucose tolerance beverage.

3. Draw blood at 1 and 2 hours after ingestion of glucose tolerance beverage.


Specimen Collection:

Specimen Type: Plasma

Container/Tube: Light-green top (lithium heparin gel)

Specimen Volume: 1 mL

Collection Instructions:

1. Spin down within 30 minutes of draw.

2. Avoid hemolysis.

3. Label tube(s) with patient’s name (first and last), date of birth, and date and actual time of draw.

Specimen Transport Temperature

Refrigerated/Ambient <8 hours OK/Frozen NO

Reference Values

Diagnosis of Gestational Diabetes Mellitus (GDM) is made when any of the following glucose values are exceeded:

Fasting ≥ 92 mg/dL

1 Hour ≥ 180 mg/dL

2 Hour ≥ 153 mg/dL 

Critical values (automatic call-back): 45 mg/dL or 450 mg/dL

Day(s) Test Set Up

Monday through Friday

Test Classification and CPT Coding