Glucose Tolerance Screen (Gestational), Plasma or Serum

Test Code

Alias/See Also

CPT Codes

Preferred Specimen
1.0 mL plasma from Green top (Lithium Heparin)

Minimum Volume
0.5 mL

Other Acceptable Specimens
1 mL serum from Serum Gel or Red Top

A copy of the Glucose Tolerance Patient Information (English / Spanish) should be given to the outpatient.
  • Fasting specimen is not necessary. 
  • Draw blood 1 hour following ingestion of 300 mL of water and 50 g of Glucola supplied.

Specimen Stability
Temperature Time
Ambient 8 hours
Refrigerated 72 hours

Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Gross hemolysis
For NCMC only: Gross lipemia if plasma - Serum specimen needed if Grossly Lipemic.

Hexokinase Bichromatic Endpoint

Setup Schedule
Monday through Sunday; Continuously

Report Available
Same day

Reference Range
≤134 mg/dL

Clinical Significance
Gestational diabetes is carbohydrate intolerance of variable severity with onset or first recognition during the present pregnancy. The diabetes usually disappears after the birth of the baby but may be associated with an increased risk of diabetes in the mother.

Performing Laboratory
Banner Fort Collins Medical Center Laboratory
Mckee Medical Center Laboratory
North Colorado Medical Center Laboratory
Summit View Laboratory

The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.