Question: I’m trying to figure out how to bill for this Glucose 2 hour test. I have been finding conflicting answers. Patient had a fasting glucose done first and then a post glucose done at 2 hours. Would there be two lab codes for the fasting and post, or is there one that would cover them both? Does it make a difference that the test ordered as a GTT Post Prandial Blood Sugar did not include 3 specimens? South Carolina Subscriber Answer: CPT® code 82950 (Glucose; post glucose dose [includes glucose]) represents a one specimen glucose tolerance test (whether done at 1 hour or 2 hours after ingesting the glucose). This does not include the fasting glucose that is done first as represented by 82947 (Glucose; quantitative, blood [except reagent strip]). But all labs now do a fasting, followed by glucose, and then testing when a 1 hour or 2 hour GTT is ordered. The 3 hour GTT (82951, Glucose; tolerance test (GTT), 3 specimens (includes glucose)), however, does include a fasting glucose followed by two more blood samplings to test the glucose levels after giving the glucose to drink. Bottom line: Your provider must order the test they want. If they did not order a fasting glucose (82947) then you would only order the 82950 for the 1 or 2 hour GTT. You need to discuss this with your providers.