CPT code 91037: Esophageal impedance, one hour or less2026 Medicare rate & RVUs in Illinois
Reports a short-duration esophageal impedance study used to assess bolus movement and reflux, including nonacid reflux, with interpretation and a report.
Medicare pays $175.36–$193.55 for 91037 in the office in Illinois, from Rest of Illinois to Suburban Chicago, IL. Which amount applies depends on the service address.
Medicare allowed amount for participating (non-QP) physicians, before deductible, coinsurance and claim adjustments. Not a patient’s bill or a hospital charge.
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On this page 9 sections
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 in Illinois
The same RVUs, adjusted for each area’s costs. Open a locality for its calculation, history and nearby areas.
4 payment localities
$175.36 to $193.55
| Payment locality | Office | Facility |
|---|---|---|
| Chicago, IL | $191.40 | Unavailable |
| East St. Louis, IL | $177.49 | Unavailable |
| Rest of Illinois | $175.36 | Unavailable |
| Suburban Chicago, IL | $193.55 | Unavailable |
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.
How the rate is built · 91037
RVUs × geographic indexes × conversion factor
Work0.95
0.95 RVUs× 1.000 GPCI
Practice expense4.59
4.59 RVUs× 1.000 GPCI
Malpractice0.07
0.07 RVUs× 1.000 GPCI
Adjusted RVUs
5.6100
Conversion factor
$33.4009
Medicare rate
$187.38
Every GPCI starts at 1.000, the national rate. Enter a ZIP or drag a slider.
Payment rules and modifiers for 91037
The CMS indicators that decide how 91037 is paid alongside other services.
CMS payment indicators · 91037
Esophageal impedance, one hour or less
| Rule | CMS value | What it means |
|---|---|---|
| Global period | 000 | Same-day global: pre- and post-op care on the day of the procedure is included. |
| Multiple procedures | 0 | No multiple-procedure reduction. |
| Bilateral (modifier 50) | 0 | The 150% bilateral adjustment doesn’t apply. |
| Assistant at surgery (80/81/82/AS) | 0 | Not paid without supporting documentation. |
| Co-surgeons (62) | 0 | Not permitted. |
| Team surgery (66) | 0 | Not permitted. |
| Professional/technical | 1 | Diagnostic test with separate professional (26) and technical (TC) components. |
What modifiers do to the payment
Modifier 26 · payment effect
With and without the modifier
91037 without 26 · national office
$187.38
Esophageal impedance, one hour or less
91037-26 · Professional component
$51.44
Pays only the interpretation and report.
91037 compared with similar codes
Compare codes · National
5 codes, side by side
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.
91037 billing questions
How is 91037 distinguished from 91038?
Use 91037 for an impedance recording of one hour or less. Use 91038 when the recording exceeds one hour.
Can the interpretation and equipment portions be billed separately?
Yes. Modifier 26 identifies the professional interpretation, and modifier TC identifies the technical service; billing without either modifier represents the global service.
Is this the same test as esophageal manometry?
No. Impedance evaluates movement of liquid or gas and reflux events, while 91010 reports an esophageal motility study. Select the code that matches the study actually performed and documented.
Can modifier 50 be used?
No. Bilateral adjustment is inappropriate for this service.
What documentation supports reporting 91037?
Document the impedance study, its recording duration, measurements, analysis, interpretation, and report. The record should support a duration of one hour or less.
Are surgical team modifiers payable with this code?
Co-surgeon and team-surgery billing are not permitted. Assistant-at-surgery payment requires documentation of medical necessity.
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
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