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.
Gastroesophageal reflux impedance testing, identified by CPT® Code 91038, is a specialized diagnostic procedure designed to assess the function of the esophagus, particularly in relation to gastroesophageal reflux disease (GERD). This test evaluates esophageal peristalsis, which is the wave-like muscle contractions that move food down the esophagus, and monitors both acidic and non-acidic reflux over an extended duration, specifically from greater than one hour up to 24 hours. The procedure involves the placement of a nasal catheter equipped with intraluminal impedance electrodes, which are sensors that detect changes in electrical resistance as the bolus of fluid passes through the esophagus. The distal impedance electrode is strategically positioned approximately 5 cm above the distal esophageal sphincter to accurately capture the dynamics of esophageal function. During the test, the patient ingests a saline solution followed by a viscous material, allowing for comprehensive analysis of bolus transit times and the esophagus's effectiveness in moving contents into the stomach. The data collected by the electrodes is crucial for the physician's evaluation of esophageal function, leading to a detailed written report that aids in diagnosis and treatment planning. For tests lasting less than one hour, CPT® Code 91037 should be utilized.
© Copyright 2026 Coding Ahead. All rights reserved.
The gastroesophageal reflux impedance test (CPT® Code 91038) is indicated for the evaluation of patients experiencing symptoms related to gastroesophageal reflux disease (GERD) and other esophageal disorders. The following conditions may warrant the performance of this test:
The procedure for the gastroesophageal reflux impedance test (CPT® Code 91038) involves several key steps to ensure accurate measurement and analysis of esophageal function:
After the gastroesophageal reflux impedance test (CPT® Code 91038) is completed, the patient may experience some minor discomfort due to the catheter insertion, but this typically resolves quickly. There are no specific post-procedure care requirements mentioned; however, patients are generally advised to resume normal activities unless otherwise directed by their physician. The physician will review the recorded data and provide a detailed report, which may include recommendations for further evaluation or treatment based on the findings of the test.
| Short Descr | ESOPH IMPED FUNCT TEST > 1HR | Medium Descr | ESOPHGL FUNCJ G-ESOP RFLX IMPD ELTRD PROLNG | Long Descr | Esophageal function test, gastroesophageal reflux test with nasal catheter intraluminal impedance electrode(s) placement, recording, analysis and interpretation; prolonged (greater than 1 hour, up to 24 hours) | Status Code | Active Code | Global Days | 000 - Endoscopic or Minor Procedure | PC/TC Indicator (26, TC) | 1 - Diagnostic Tests for Radiology Services | Multiple Procedures (51) | 0 - No payment adjustment rules for multiple procedures apply. | Bilateral Surgery (50) | 0 - 150% payment adjustment for bilateral procedures does NOT apply. | Physician Supervisions | 09 - Concept does not apply. | Assistant Surgeon (80, 82) | 0 - Payment restriction for assistants at surgery applies to this procedure... | Co-Surgeons (62) | 0 - Co-surgeons not permitted for this procedure. | Team Surgery (66) | 0 - Team surgeons not permitted for this procedure. | Diagnostic Imaging Family | 99 - Concept Does Not Apply | APC Status Indicator | Procedure or Service, Not Discounted when Multiple | Type of Service (TOS) | 1 - Medical Care | Berenson-Eggers TOS (BETOS) | P6C - Minor procedures - other (Medicare fee schedule) | MUE | 1 | CCS Clinical Classification | 97 - Other gastrointestinal diagnostic procedures |
| 26 | Professional component: certain procedures are a combination of a physician or other qualified health care professional component and a technical component. when the physician or other qualified health care professional component is reported separately, the service may be identified by adding modifier 26 to the usual procedure number. | GC | This service has been performed in part by a resident under the direction of a teaching physician | 51 | Multiple procedures: when multiple procedures, other than e/m services, physical medicine and rehabilitation services or provision of supplies (eg, vaccines), are performed at the same session by the same individual, the primary procedure or service may be reported as listed. the additional procedure(s) or service(s) may be identified by appending modifier 51 to the additional procedure or service code(s). note: this modifier should not be appended to designated "add-on" codes (see appendix d). | 52 | Reduced services: under certain circumstances a service or procedure is partially reduced or eliminated at the discretion of the physician or other qualified health care professional. under these circumstances the service provided can be identified by its usual procedure number and the addition of modifier 52, signifying that the service is reduced. this provides a means of reporting reduced services without disturbing the identification of the basic service. note: for hospital outpatient reporting of a previously scheduled procedure/service that is partially reduced or cancelled as a result of extenuating circumstances or those that threaten the well-being of the patient prior to or after administration of anesthesia, see modifiers 73 and 74 (see modifiers approved for asc hospital outpatient use). | 53 | Discontinued procedure: under certain circumstances, the physician or other qualified health care professional may elect to terminate a surgical or diagnostic procedure. due to extenuating circumstances or those that threaten the well being of the patient, it may be necessary to indicate that a surgical or diagnostic procedure was started but discontinued. this circumstance may be reported by adding modifier 53 to the code reported by the individual for the discontinued procedure. note: this modifier is not used to report the elective cancellation of a procedure prior to the patient's anesthesia induction and/or surgical preparation in the operating suite. for outpatient hospital/ambulatory surgery center (asc) reporting of a previously scheduled procedure/service that is partially reduced or cancelled as a result of extenuating circumstances or those that threaten the well being of the patient prior to or after administration of anesthesia, see modifiers 73 and 74 (see modifiers approved for asc hospital outpatient use). | 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. | AQ | Physician providing a service in an unlisted health professional shortage area (hpsa) | CC | Procedure code change (use 'cc' when the procedure code submitted was changed either for administrative reasons or because an incorrect code was filed) | CR | Catastrophe/disaster related | TC | Technical component; under certain circumstances, a charge may be made for the technical component alone; under those circumstances the technical component charge is identified by adding modifier 'tc' to the usual procedure number; technical component charges are institutional charges and not billed separately by physicians; however, portable x-ray suppliers only bill for technical component and should utilize modifier tc; the charge data from portable x-ray suppliers will then be used to build customary and prevailing profiles | XS | Separate structure, a service that is distinct because it was performed on a separate organ/structure |
|
Date
|
Action
|
Notes
|
|---|---|---|
| 2013-01-01 | Changed | Short Descriptor changed. |
| 2005-01-01 | Added | First appearance in code book in 2005. |
Get instant expert-level medical coding assistance.