CPT® Code 82946

The glucagon tolerance test, identified by CPT® Code 82946, is a laboratory procedure designed to assess the body's response to glucagon, a hormone that plays a critical role in glucose metabolism. This test measures the levels of glucose and lactate in the blood after glucagon administration. Glucagon is produced by the pancreas and functions to elevate blood sugar levels by prompting the liver to release glycogen, a stored form of glucose, through a process known as glycogenolysis. The glucagon tolerance test is particularly useful in the evaluation and diagnosis of glycogen storage diseases, such as von Gierke's disease and Cori's disease, which are characterized by the body's inability to properly store and utilize glycogen. Prior to undergoing the test, patients are required to fast for a minimum of 14 hours to ensure accurate baseline measurements. During the procedure, an intravenous (IV) line may be established, which can be reported separately, to facilitate the administration of glucagon and the collection of blood samples. Blood samples for glucose and lactate levels are collected at specified intervals—30, 60, 90, and 120 minutes post-injection—either from the IV line or through a separately reportable venipuncture. The analysis of serum or plasma for glucose and lactate is conducted using a quantitative enzymatic method, providing essential data for the assessment of the patient's metabolic response to glucagon.