Need help choosing the right code?
Ask CasePilot about procedures, modifiers, bundling, and coding guidance.
Try CasePilot© Copyright 2026 American Medical Association. All rights reserved.
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.
© Copyright 2026 Coding Ahead. All rights reserved.
The glucose tolerance test (GTT) is indicated for the following conditions:
The glucose tolerance test (GTT) procedure involves several critical steps to ensure accurate measurement of glucose metabolism. First, the patient must fast for a minimum of 8 hours prior to the test to establish a baseline blood glucose level. A blood sample is then obtained through venipuncture, which serves as the baseline measurement. Following this, the patient is administered a concentrated glucose solution, typically 75 grams, or 100 grams if the patient is pregnant. This oral dose of glucose is crucial for stimulating the body's insulin response. After the ingestion of glucose, blood samples are collected at specific intervals: 60, 120, and 180 minutes post-ingestion. Each of these samples is obtained through separate venipuncture procedures. The plasma from these samples is analyzed using a quantitative enzymatic method to determine the glucose levels in the blood. In cases where lactose intolerance or malabsorption disorders are being tested, the procedure slightly differs. A baseline blood glucose level is still obtained, but the patient is given a 50-gram dose of glucose. Blood samples are then collected at 30, 60, 120, and 180 minutes after ingestion. The first three blood samples collected during the GTT are reported using CPT® code 82951, while any additional samples taken are reported using CPT® code 82952.
After the glucose tolerance test is completed, patients may experience varying levels of fatigue or discomfort due to the glucose ingestion. It is generally recommended that patients resume their normal activities unless otherwise advised by their healthcare provider. The results of the test will be analyzed and interpreted by the physician, who will discuss the findings with the patient. Depending on the results, further testing or interventions may be necessary to address any identified glucose metabolism issues. Patients should be informed about the importance of following up with their healthcare provider to understand their results and any potential implications for their health.
| Short Descr | GLUCOSE TOLERANCE TEST (GTT) | Medium Descr | GLUCOSE TOLERANCE TEST GTT 3 SPECIMENS | Long Descr | Glucose; tolerance test (GTT), 3 specimens (includes glucose) | Status Code | Statutory Exclusion (from MPFS, may be paid under other methodologies) | Global Days | XXX - Global Concept Does Not Apply | PC/TC Indicator (26, TC) | 9 - Not Applicable | Multiple Procedures (51) | 9 - Concept does not apply. | Bilateral Surgery (50) | 9 - Concept does not apply. | Physician Supervisions | 09 - Concept does not apply. | Assistant Surgeon (80, 82) | 9 - Concept does not apply. | Co-Surgeons (62) | 9 - Concept does not apply. | Team Surgery (66) | 9 - Concept does not apply. | Diagnostic Imaging Family | 99 - Concept Does Not Apply | CLIA Waived (QW) | Yes | APC Status Indicator | Service Paid under Fee Schedule or Payment System other than OPPS | Type of Service (TOS) | 5 - Diagnostic Laboratory | Berenson-Eggers TOS (BETOS) | T1E - Lab tests - glucose | MUE | 1 | CCS Clinical Classification | 233 - Laboratory - Chemistry and Hematology |
This is a primary code that can be used with these additional add-on codes.
| 82952 | Addon Code MPFS Status: Statutory exclusion (from MPFS, may be paid under other methodologies) APC Q4 PUB 100 CPT Assistant Article Glucose; tolerance test, each additional beyond 3 specimens (List separately in addition to code for primary procedure) |
| 90 | Reference (outside) laboratory: when laboratory procedures are performed by a party other than the treating or reporting physician or other qualified health care professional, the procedure may be identified by adding modifier 90 to the usual procedure number. | QW | Clia waived test | Q5 | Service furnished under a reciprocal billing arrangement by a substitute physician or by a substitute physical therapist furnishing outpatient physical therapy services in a health professional shortage area, a medically underserved area, or a rural area | 59 | Distinct procedural service: under certain circumstances, it may be necessary to indicate that a procedure or service was distinct or independent from other non-e/m services performed on the same day. modifier 59 is used to identify procedures/services, other than e/m services, that are not normally reported together, but are appropriate under the circumstances. documentation must support a different session, different procedure or surgery, different site or organ system, separate incision/excision, separate lesion, or separate injury (or area of injury in extensive injuries) not ordinarily encountered or performed on the same day by the same individual. however, when another already established modifier is appropriate it should be used rather than modifier 59. only if no more descriptive modifier is available, and the use of modifier 59 best explains the circumstances, should modifier 59 be used. note: modifier 59 should not be appended to an e/m service. to report a separate and distinct e/m service with a non-e/m service performed on the same date, see modifier 25. | 91 | Repeat clinical diagnostic laboratory test: in the course of treatment of the patient, it may be necessary to repeat the same laboratory test on the same day to obtain subsequent (multiple) test results. under these circumstances, the laboratory test performed can be identified by its usual procedure number and the addition of modifier 91. note: this modifier may not be used when tests are rerun to confirm initial results; due to testing problems with specimens or equipment; or for any other reason when a normal, one-time, reportable result is all that is required. this modifier may not be used when other code(s) describe a series of test results (eg, glucose tolerance tests, evocative/suppression testing). this modifier may only be used for laboratory test(s) performed more than once on the same day on the same patient. | GA | Waiver of liability statement issued as required by payer policy, individual case | GW | Service not related to the hospice patient's terminal condition | GY | Item or service statutorily excluded, does not meet the definition of any medicare benefit or, for non-medicare insurers, is not a contract benefit | GZ | Item or service expected to be denied as not reasonable and necessary | KX | Requirements specified in the medical policy have been met | Q4 | Service for ordering/referring physician qualifies as a service exemption | XS | Separate structure, a service that is distinct because it was performed on a separate organ/structure | XU | Unusual non-overlapping service, the use of a service that is distinct because it does not overlap usual components of the main service |
|
Date
|
Action
|
Notes
|
|---|---|---|
| 2010-01-01 | Changed | Code description changed. |
| Pre-1990 | Added | Code added. |
Get instant expert-level medical coding assistance.