CPT® Code 82951

The glucose tolerance test (GTT) is a laboratory procedure designed to assess the body's ability to metabolize glucose, a vital sugar that serves as a primary energy source for cells. This test is particularly important in diagnosing conditions such as gestational diabetes, diabetes mellitus, and impaired glucose tolerance. It may also be utilized to evaluate lactose intolerance and malabsorption disorders. The test begins with the patient fasting for at least 8 hours to ensure accurate baseline measurements of blood glucose levels. A baseline blood sample is collected through venipuncture, which is a standard procedure for obtaining blood samples. Following this, the patient ingests a specified amount of concentrated glucose, typically 75 grams, although a higher dose of 100 grams is administered for pregnant patients. Subsequent blood samples are taken at designated intervals—60, 120, and 180 minutes after glucose ingestion—to monitor how the body processes the glucose. The plasma from these samples is analyzed using a quantitative enzymatic method to determine glucose levels. In cases where lactose intolerance or malabsorption is suspected, a different protocol is followed, starting with a baseline blood sample, followed by a 50-gram glucose dose, with blood samples collected at 30, 60, 120, and 180 minutes. The first three blood samples collected during the GTT are reported using CPT® code 82951, while any additional samples are reported with CPT® code 82952.