Summary & Overview

CPT 82951: Three-Point Oral Glucose Tolerance Test

CPT code 82951 represents a three-point oral glucose tolerance test that measures blood glucose at a fasting baseline and at two additional timed intervals after an oral glucose challenge. This diagnostic laboratory procedure is nationally relevant because it is a standard clinical tool for evaluating glucose regulation and diagnosing impaired glucose tolerance and diabetes, impacting screening and disease management across outpatient and laboratory settings. Key national payers addressed in the analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise explanation of the clinical context for the three-sample oral glucose tolerance test, typical sites of service where the test is performed, and the importance of standardized timing and specimen handling. The publication also summarizes billing and coverage considerations commonly relevant to national payers, outlines common billing modifiers provided in the input, and highlights areas where policy updates or local medical necessity rules can affect coverage and reimbursement. Where specific payer policy details, associated taxonomies, ICD-10 pairings, or related service-line data are not included in the input, the document notes that detailed payer-specific policy content is not available in the source material. This piece serves as a practical reference for clinicians, billing staff, and policy analysts seeking a national-level overview of CPT code 82951 and its role in diagnostic glucose testing.

AetnaBlue Cross Blue ShieldCigna HealthUnitedHealthcareMedicare82951CPToral glucose tolerance testlaboratoryglucose testingdiagnostic testendocrinologyambulatory care

Billing Code Overview

CPT code 82951 describes a laboratory procedure that measures blood glucose at three timed points: an initial fasting sample and two subsequent samples taken at specified intervals after the patient ingests an oral glucose load. This service is a three-point oral glucose tolerance test used to assess glucose metabolism and help diagnose conditions such as impaired glucose tolerance and diabetes.

Service type: Diagnostic laboratory test (oral glucose tolerance testing)
Typical site of service: Clinical laboratory, hospital outpatient laboratory, or ambulatory care setting where timed blood draws and oral glucose administration can be performed

Clinical & Coding Specifications

Clinical Context

A typical patient undergoing 82951 is an adult evaluated for impaired glucose tolerance or suspected diabetes. The patient arrives fasting in the morning after an overnight fast. Baseline venous blood is drawn to measure fasting plasma glucose. The patient then ingests a standardized oral glucose solution (commonly 75 g for adults). Timed venous blood draws are obtained at specified intervals (commonly 1 hour and 2 hours) to measure plasma glucose concentrations. The clinical workflow includes verification of fasting status, informed consent for the oral glucose tolerance test, administration of the glucose load, timed specimen collection by phlebotomy, specimen labeling and transport to the laboratory, analysis by the laboratory analyst, and result reporting to the ordering clinician. Typical indications include screening for gestational diabetes in pregnancy, evaluation of symptoms suggestive of hyperglycemia (polyuria, polydipsia, unexplained weight loss), or monitoring borderline abnormal fasting glucose. Typical site of service is an outpatient clinic, ambulatory infusion/diagnostic center, or hospital outpatient laboratory where phlebotomy and timed monitoring can be performed safely. Patient preparation instructions include fasting for at least 8 hours, avoidance of smoking or vigorous activity before testing, and continuation of usual medications unless otherwise directed by the clinician.

Coding Specifications

Modifier	Description	When to Use
`26`	Professional component	When billing only the physician or laboratorian professional interpretation component, if applicable.
`59`	Distinct procedural service	When the oral glucose tolerance test is a distinct service separate from other laboratory procedures billed on the same day.
`52`	Reduced services	When the test is partially reduced or aborted but still resulted in partial testing.
`53`	Discontinued procedure	When the test is started but discontinued due to patient adverse event or intolerance.
`91`	Repeat clinical diagnostic laboratory test	When the entire oral glucose tolerance test is repeated within a short time frame due to lab error or clinical necessity.
`90`	Reference (outside) laboratory	When the testing was performed by an outside/reference laboratory and only the reference lab charge is billed.
`TC`	Technical component	When billing only the laboratory technical component (equipment, supplies, technician) for the assay.
`QW`	CLIA waived test	When the glucose measurements were performed using a CLIA-waived point-of-care instrument (if applicable).
`XE`	Separate encounter	When the test is performed during a separate encounter by a different practitioner and needs to be reported distinct from other same-day services.
`XS`	Separate structure	When the test is performed on a separate anatomical site or structure and must be reported distinct from other services.
`XU`	Unusual non-overlapping service	When the test represents a distinct non-overlapping service compared with other lab procedures performed the same day.

Taxonomy Code	Specialty	Notes
207Q00000X	Pathology & Laboratory	Clinical laboratory directors and laboratory medicine specialists overseeing testing.
207L00000X	Clinical Laboratory	Medical technologists and clinical laboratory scientists performing assays and analysis.
207K00000X	Clinical Pathology	Physicians providing oversight and interpretation of laboratory results.
208D00000X	Endocrinology	Ordering and managing diagnostic testing for glucose metabolism disorders.
208000000X	Family Medicine	Primary care clinicians ordering and following up on oral glucose tolerance testing.

Related Diagnoses

ICD-10 Code	Description	Clinical Relevance
`E11.9`	Type 2 diabetes mellitus without complications	Common diagnosis assessed or screened for with an oral glucose tolerance test in patients with risk factors or suggestive symptoms.
`R73.01`	Impaired fasting glucose	Indicates abnormal fasting glucose; OGT may clarify impaired glucose tolerance status.
`R73.02`	Impaired glucose tolerance (oral)	Directly assessed by the oral glucose tolerance test and used to diagnose prediabetes.
`O24.41`	Gestational diabetes mellitus, diet controlled	The oral glucose tolerance test is standard for diagnosing gestational diabetes in pregnancy.
`E08.9`	Diabetes mellitus due to underlying condition, without complications	OGT may be used in evaluating hyperglycemia secondary to other conditions.

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`82947`	Glucose; quantitative, blood (except reagent strip)	May be billed for a single glucose measurement such as fasting glucose when a full oral glucose tolerance test is not performed or for interim checks.
`82950`	Glucose; blood, reagent strip	Used for point-of-care capillary glucose testing (fingerstick) often performed for immediate monitoring during tolerance testing; separate from laboratory-based `82951`.
`83036`	Hemoglobin; glycosylated (A1c)	Often ordered alongside `82951` to assess longer-term glycemic control and complement results of the oral glucose tolerance test.
`81002`	Urinalysis, by dip stick or tablet reagent (non-automated), without microscopy	May be performed concurrently to evaluate for glucosuria or other urinary findings during metabolic evaluation.
`82962`	Glucose tolerance test, 4 post-glucose blood draws (each additional beyond 3)	Represents extended glucose tolerance testing with additional timed measurements beyond the standard three; may be performed when a different protocol is indicated.