Summary & Overview
CPT 91065: Hydrogen or Methane Breath Test for Gastrointestinal Function
CPT code 91065 identifies a hydrogen or methane breath test used to diagnose gastrointestinal conditions such as lactose deficiency, fructose intolerance, small intestinal bacterial overgrowth, and to measure oro–cecal transit time. The test is noninvasive, requires fasting (commonly 8–12 hours), and is widely performed in outpatient and ambulatory settings. Nationally, this code matters because breath testing supports targeted clinical management of common digestive complaints and can affect diagnostic pathways and utilization of follow-up procedures.
Key payers covered in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find an overview of clinical indications tied to the code, typical sites of service, and the operational context for use of 91065 in outpatient gastroenterology. The publication summarizes payer coverage considerations, common modifier usage, and how the procedure fits into diagnostic workflows.
The report addresses benchmarks and policy-relevant items such as payer coverage patterns, coding practice implications, and scenarios that commonly prompt testing. It also provides clinical context that clarifies when breath testing is likely to be ordered and what information the test yields for patient management. Data not available in the input are noted where applicable.
Billing Code Overview
CPT code 91065 describes a hydrogen or methane breath test, a noninvasive diagnostic procedure used to evaluate gastrointestinal function. The test measures hydrogen or methane concentrations in exhaled breath to identify conditions such as lactose deficiency, fructose intolerance, small intestinal bacterial overgrowth (SIBO), and to assess oro–cecal transit time. A required preparatory step is fasting (typically 8–12 hours) before specimen collection.
Service type: Diagnostic breath testing for gastrointestinal dysfunction
Typical site of service: Outpatient clinic, gastroenterology office, or ambulatory testing center
Clinical & Coding Specifications
Clinical Context
A 34-year-old outpatient presents to a gastroenterology clinic with several months of bloating, abdominal pain, and frequent loose stools that worsen after dairy ingestion. The gastroenterologist documents a focused history and physical, determines that carbohydrate malabsorption or small intestinal bacterial overgrowth (SIBO) is in the differential, and orders a hydrogen/methane breath test to evaluate for lactose intolerance and/or SIBO. The patient is instructed to fast for 8–12 hours, avoid antibiotics and probiotics for at least 2–4 weeks, and follow a preparatory diet the day before testing. On the day of service the patient arrives at the ambulatory clinic or outpatient testing center. A trained technician confirms identity, reviews preparation compliance, records baseline breath samples, administers the substrate (e.g., lactose or glucose or lactulose), and collects timed breath samples for hydrogen and methane measurement. The procedure is noninvasive, typically performed while the patient is seated, and the results are interpreted by the ordering clinician. Typical sites of service include an outpatient gastroenterology clinic, ambulatory surgery center (for billing location purposes), or hospital outpatient department when performed as an outpatient diagnostic test. The service type is an outpatient diagnostic breath test.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
25 | Significant, separately identifiable evaluation and management service on the same day | Use when a qualifying E/M is provided and documented the same day as the breath test |