Glucose, Gestational Challenge

Test Code

GCT

Preferred Specimen

1 mL fluoride/oxalate plasma

Patient Preparation
Fasting required. Fasting is defined as no consumption of food or beverage other than water for at least 8 hours before testing

Minimum Volume

0.5 mL

Other Acceptable Specimens

Fluoride/oxalate whole blood

Instructions

Have patient ingest a 50 g load of glucose. Draw specimen 1 hour later. Label each specimen with the specific draw time. Note: The test should be performed between weeks 24 and 28 of gestation.

Transport Container

Fluoride/oxalate (gray-top) tubes

Transport Temperature

Room temperature

Specimen Stability

Whole blood (gray-top) tube:
Room temperature: 24 hours
Refrigerated: 72 hours

Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)

Tubes other than gray top tubes

Methodology
Spectrophotometry (SP)

Setup Schedule

24/7

Report Available

Same day

Limitations

Glucose levels may be depressed if sample is left on clot for an excessive length of time.

Reference Range

Glucose, Gestational Screen (50g)-140 cutoff

<140

mg/dL

Clinical Significance

A value of 140 mg/dL or greater indicates the need for a full diagnostic, gestational glucose tolerance performed in the fasting state to determine if the patient has gestational diabetes.

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.