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Test Code GESTL1 Glucose Tolerance, Gestational

Important Note

Allen Laboratory Test

All pregnant women should be screened for glucose intolerance prior to performing this test. See 1 hr OB Glucose Tolerance Test.

Additional Codes

Epic ID LAB2491

 

Specimen Requirements

The patient must be fasting (10-16 hours) and in relatively good health (ie., not nauseous).

Draw lithium heparin whole blood for fasting glucose.

If glucose is >140 mg/dl do not give glucose solution. If glucose is <140 mg/dl, give 100 gms (296 ml of S/P Glucose 100 orange) glucose solution. Drink within 5 minutes. No food during test. Water according to thirst. No caffeine or nicotine during test. Vomiting within ½ hour of ingestion of solution voids test.

Collect: 1.0mL of Lithium heparinized plasma or serum at 1, 2, and 3 hours after ingestion of glucose solution.

Serum or plasma must be separated from cells within 2 hours of collection.

Stability/Transport

Whole Blood Lithium Heparin: 15 minutes at room temperature

SST serum or heparinized plasma: 2 hours at room temp, 4 days refrigerated

 

Performing Lab

Allen Hospital Laboratory

Day(s) Performed

Daily

Report Available

3 1/2 hours

Reference Ranges

GEST1H: 65-179 mg/dL

GEST2H: 65-154 mg/dL

GEST3H: 65-139 mg/dL

Impaired glucose tolerance is noted when any two or more of the following are exceeded: Fasting = > 95 mg/dl, 1 Hour = > 180 mg/dl, 2 Hour = > 155 mg/dl, or 3 Hour = > 140 mg/dl.

Glucose tolerance tests should be performed in the morning as there is a diurnal variation with tolerance in the afternoon, significantly decreased from that in the morning.

Critical Value: <50 mg/dL or >400 mg/dL

CPT Code Information

82951