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Official Description

Esophagus, gastroesophageal reflux test; with mucosal attached telemetry pH electrode placement, recording, analysis and interpretation

© Copyright 2026 American Medical Association. All rights reserved.

Common Language Description

The CPT® Code 91035 refers to a specialized diagnostic procedure known as the esophagus gastroesophageal reflux test, which is specifically designed to assess gastroesophageal reflux disease (GERD). This test involves the placement of a mucosal attached telemetry pH electrode, which is a sophisticated device that measures the acidity levels in the esophagus. The procedure is particularly beneficial for patients who exhibit symptoms indicative of GERD or for those who have been diagnosed with GERD but are not experiencing relief from standard treatment options. The test utilizes a capsule that contains a pH probe, a battery, and a transmitter, which is introduced into the esophagus through the nose or mouth. Once positioned, the capsule adheres to the esophageal mucosa, allowing for continuous monitoring of pH levels over a period of 24 to 48 hours. This data is crucial for understanding the frequency and duration of acid exposure in the esophagus, which can help guide treatment decisions. The procedure is non-invasive, and the capsule is designed to detach naturally from the esophagus after a few days, passing through the digestive system without the need for removal. The results of the test are analyzed by a physician, who then provides a comprehensive report based on the recorded data, aiding in the diagnosis and management of GERD.

© Copyright 2026 Coding Ahead. All rights reserved.

1. Indications

The esophagus gastroesophageal reflux test (CPT® Code 91035) is indicated for patients presenting with symptoms associated with gastroesophageal reflux disease (GERD). The following conditions warrant the performance of this test:

  • Symptoms of GERD Patients exhibiting classic symptoms such as heartburn, regurgitation, and difficulty swallowing may require this test to confirm a diagnosis of GERD.
  • Known GERD with Treatment Failure Individuals diagnosed with GERD who are not responding adequately to standard treatment regimens may undergo this test to evaluate the effectiveness of their current management and to guide further therapeutic decisions.

2. Procedure

The procedure for the esophagus gastroesophageal reflux test involves several key steps to ensure accurate placement and data collection:

  • Step 1: Catheter Insertion A catheter containing a capsule with a pH probe, battery, and transmitter is introduced into the patient's nose or mouth and carefully advanced into the esophagus. This step is crucial for ensuring that the capsule is positioned correctly to monitor pH levels accurately.
  • Step 2: Capsule Attachment Once the capsule reaches the appropriate location in the esophagus, it is attached to the esophageal mucosa using a clip. This secure attachment allows the capsule to remain in place during the monitoring period, ensuring reliable data collection.
  • Step 3: Catheter Removal After the capsule is successfully attached, the catheter is removed from the patient's body. This step is important as it allows the patient to continue with their daily activities without the discomfort of the catheter.
  • Step 4: External Recorder Usage The patient is provided with an external recorder that communicates wirelessly with the transmitter in the capsule. This recorder captures pH data over a 24 to 48-hour period, allowing for continuous monitoring of acid exposure in the esophagus.
  • Step 5: Patient Engagement During the monitoring period, the patient is instructed to initiate recordings by pressing a button on the recorder whenever they experience symptoms, before, during, and after meals, and when lying down. This self-initiated data collection is vital for correlating symptoms with pH levels.
  • Step 6: Data Return After the monitoring period, the patient returns to the physician's office to return the external recorder. The data collected during the test is then analyzed by the physician.
  • Step 7: Capsule Detachment The capsule is designed to detach from the esophageal mucosa naturally within 5 to 7 days and will be passed in the stool, eliminating the need for any invasive removal procedures.

3. Post-Procedure

Post-procedure care for the esophagus gastroesophageal reflux test primarily involves the return of the external recorder to the physician's office. The physician will analyze the data captured during the monitoring period to assess the pH levels in the esophagus. The results will be compiled into a comprehensive report, which will be discussed with the patient during a follow-up appointment. It is important for patients to understand that the capsule will detach from the esophagus and pass naturally, and they should not experience any discomfort related to the capsule after the procedure. Patients are advised to monitor their symptoms and report any unusual occurrences to their healthcare provider.

Short Descr G-ESOPH REFLX TST W/ELECTROD
Medium Descr GASTROESOPHAG REFLX TEST W/TELEMTRY PH ELTRD
Long Descr Esophagus, gastroesophageal reflux test; with mucosal attached telemetry pH electrode placement, recording, analysis and interpretation
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
ASC Payment Indicator Radiology service paid separately when provided integral to a surgical procedure on ASC list; payment based on OPPS relative payment weight.
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.
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
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.
GC This service has been performed in part by a resident under the direction of a teaching physician
SG Ambulatory surgical center (asc) facility service
25 Significant, separately identifiable evaluation and management service by the same physician or other qualified health care professional on the same day of the procedure or other service: it may be necessary to indicate that on the day a procedure or service identified by a cpt code was performed, the patient's condition required a significant, separately identifiable e/m service above and beyond the other service provided or beyond the usual preoperative and postoperative care associated with the procedure that was performed. a significant, separately identifiable e/m service is defined or substantiated by documentation that satisfies the relevant criteria for the respective e/m service to be reported (see evaluation and management services guidelines for instructions on determining level of e/m service). the e/m service may be prompted by the symptom or condition for which the procedure and/or service was provided. as such, different diagnoses are not required for reporting of the e/m services on the same date. this circumstance may be reported by adding modifier 25 to the appropriate level of e/m service. note: this modifier is not used to report an e/m service that resulted in a decision to perform surgery. see modifier 57 for significant, separately identifiable non-e/m services, see modifier 59.
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).
58 Staged or related procedure or service by the same physician or other qualified health care professional during the postoperative period: it may be necessary to indicate that the performance of a procedure or service during the postoperative period was: (a) planned or anticipated (staged); (b) more extensive than the original procedure; or (c) for therapy following a surgical procedure. this circumstance may be reported by adding modifier 58 to the staged or related procedure. note: for treatment of a problem that requires a return to the operating/procedure room (eg, unanticipated clinical condition), see modifier 78.
74 Discontinued out-patient hospital/ambulatory surgery center (asc) procedure after administration of anesthesia: due to extenuating circumstances or those that threaten the well being of the patient, the physician may terminate a surgical or diagnostic procedure after the administration of anesthesia (local, regional block(s), general) or after the procedure was started (incision made, intubation started, scope inserted, etc). under these circumstances, the procedure started but terminated can be reported by its usual procedure number and the addition of modifier 74. note: the elective cancellation of a service prior to the administration of anesthesia and/or surgical preparation of the patient should not be reported. for physician reporting of a discontinued procedure, see modifier 53.
78 Unplanned return to the operating/procedure room by the same physician or other qualified health care professional following initial procedure for a related procedure during the postoperative period: it may be necessary to indicate that another procedure was performed during the postoperative period of the initial procedure (unplanned procedure following initial procedure). when this procedure is related to the first, and requires the use of an operating/procedure room, it may be reported by adding modifier 78 to the related procedure. (for repeat procedures, see modifier 76.)
79 Unrelated procedure or service by the same physician or other qualified health care professional during the postoperative period: the individual may need to indicate that the performance of a procedure or service during the postoperative period was unrelated to the original procedure. this circumstance may be reported by using modifier 79. (for repeat procedures on the same day, see modifier 76.)
95 Synchronous telemedicine service rendered via a real-time interactive audio and video telecommunications system: synchronous telemedicine service is defined as a real-time interaction between a physician or other qualified health care professional and a patient who is located at a distant site from the physician or other qualified health care professional. the totality of the communication of information exchanged between the physician or other qualified health care professional and the patient during the course of the synchronous telemedicine service must be of an amount and nature that would be sufficient to meet the key components and/or requirements of the same service when rendered via a face-to-face interaction. modifier 95 may only be appended to the services listed in appendix p. appendix p is the list of cpt codes for services that are typically performed face-to-face, but may be rendered via a real-time (synchronous) interactive audio and video telecommunications system.
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
GP Services delivered under an outpatient physical therapy plan of care
GY Item or service statutorily excluded, does not meet the definition of any medicare benefit or, for non-medicare insurers, is not a contract benefit
GZ Item or service expected to be denied as not reasonable and necessary
PT Colorectal cancer screening test; converted to diagnostic test or other procedure
SA Nurse practitioner rendering service in collaboration with a physician
XP Separate practitioner, a service that is distinct because it was performed by a different practitioner
XS Separate structure, a service that is distinct because it was performed on a separate organ/structure
XU Unusual non-overlapping service, the use of a service that is distinct because it does not overlap usual components of the main service
Date
Action
Notes
2005-01-01 Added First appearance in code book in 2005.
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