CPT code 91037: Esophageal impedance, one hour or less2026 Medicare rate & RVUs

Medicare pays $187.38 for 91037 nationally in the office. Local office rates run $164.63–$257.55.

Medicare allowed amount for participating (non-QP) physicians, before deductible, coinsurance and claim adjustments. Not a patient’s bill or a hospital charge.

What 91037 covers

This diagnostic study uses an esophageal catheter with impedance sensors to assess movement of liquid or gas through the esophagus and identify reflux events. It can help evaluate persistent reflux symptoms, including suspected nonacid reflux, or swallowing complaints when objective information about esophageal transit is needed. Gastroenterology or esophageal motility practices commonly perform the study, with trained staff placing the catheter and a qualified clinician interpreting the findings. This code is for the recording of one hour or less; the longer-duration service is reported separately under 91038.

Report the service when the documented study includes impedance measurements, analysis, interpretation, and a report. The claim may represent the global service or the professional interpretation with modifier 26 or technical portion with modifier TC. The 0-day global period includes same-day preoperative and postoperative care. Modifier 50 is inappropriate for this service. Assistant-at-surgery payment requires documented medical necessity; co-surgeons and team surgery are not permitted.

This summary was written with AI assistance from CMS physician fee schedule data and checked against the CMS billing rules shown here. Rates on this page come directly from CMS files.

Where 91037 pays more and less

The same RVUs, adjusted for each area’s costs. Open a locality for its calculation, history and nearby areas.

109 of 109 payment localities

91037 rates by state

Office rate range in each state. Select a state to see its payment localities.

How the 91037 rate is calculated

Each of 91037’s three RVUs is multiplied by a geographic index (GPCI) for the payment locality, added up, and multiplied by the conversion factor. Drag the indexes or enter a ZIP to see what moves the rate.

Payment rules and modifiers for 91037

The CMS indicators that decide how 91037 is paid alongside other services.

What modifiers do to the payment

When to use modifier 26

91037 compared with similar codes

How to choose

91038Esophageal impedanceMore than one hour

Both report esophageal impedance testing; 91037 is for one hour or less, while 91038 is for a recording longer than one hour.

91010Esophageal manometryStandard pressure study

91010 reports esophageal motility testing. Choose 91037 when the performed study uses impedance to assess bolus movement or reflux.

91034Reflux monitoringNasal catheter pH test

91034 reports catheter-based reflux monitoring. 91037 reports an impedance study that evaluates bolus movement and reflux events.

91035Reflux testingMucosa-attached telemetry electrode

91035 reports wireless esophageal reflux monitoring; 91037 is the short-duration impedance study.

Codes related to 91037

Related codes aren’t interchangeable: bill the code that matches the service performed.

Where these rates come from

FeeBase calculates base physician payments from CMS work, practice-expense and malpractice RVUs, adjusted by each locality’s geographic indexes and the conversion factor. Services without a published rate are labeled, never given a made-up amount. Amounts are Medicare allowed amounts before claim adjustments: not a patient’s bill or a commercial rate.

CMS RVU26D · effective Oct 1, 2026 through the day before Jan 1, 2027

Open CMS sourceHow we calculate rates