Glucose Tolerance Test

Test Code

GTT

CPT Codes
82947; 82950

Includes

Fasting glucose level, glucose 2-hours post tolerance drink

Preferred Specimen

Serum (gold top) tube

Minimum Volume

0.5 mL

Other Acceptable Specimens

Lithium Heparin Plasma (green top) tube

Transport Container

Serum (gold top) tube or Lithium Heparin Plasma (green top) tube

Transport Temperature

Room Temperature or Refrigeration

Specimen Stability

Room Temperature - 24 hours; Refrigeration - 7 days

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

Quantity Not Sufficient, IV contamination

Methodology
Colorimetric

Setup Schedule

Daily upon receipt

Report Available

Upon completion of analysis

Reference Range

Fasting Glucose: 65 - 105 mg/dL
2 hour Glucose: < 140 mg/dL

Clinical Significance

Glucose is a primary cellular energy source. Fasting plasma glucose concentrations and tolerance to a dose of glucose are used to establish the diagnosis of diabetes mellitus and disorders of carbohydrate metabolism. Glucose measurements are used to monitor therapy in diabetics and in patients with dehydration, coma, hypoglycemia, insulinoma, acidosis, and ketoacidosis.

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.