print Print Back Back

Ambulatory Esophageal pH Monitoring

Policy Number: MP-138

Latest Review Date: November 2019

Category: Medical                                                                 

Policy Grade:  B


Catheter-based impedance-pH monitoring is considered not medically necessary and investigational.

Ambulatory Esophageal pH monitoring using a wireless or catheter based system may be considered medically necessary for the following clinical indications in adults and children or adolescents able to report symptoms:

  • Documentation of abnormal acid exposure in endoscopy-negative patients being considered for surgical antireflux repair;
  • Evaluation of patients after antireflux surgery who are suspected of having ongoing abnormal reflux;
  • Evaluation of patients with either normal or equivocal endoscopic findings and reflux symptoms that are refractory to proton pump inhibitor therapy;
  • Evaluation of suspected otolaryngologic manifestations of GERD (i.e., laryngitis, pharyngitis, chronic cough) that have failed to respond to at least four weeks of proton pump inhibitor therapy;
  • Evaluation of concomitant GERD in an adult-onset, nonallergic asthmatic suspected of having reflux-induced asthma.

24-hour catheter-based esophageal pH monitoring may be considered medically necessary in infants or children who are unable to report or describe symptoms of reflux with:

  • Unexplained apnea;
  • Bradycardia;
  • Refractory coughing or wheezing, stridor, or recurrent choking (aspiration);
  • Persistent or recurrent laryngitis; and
  • Recurrent pneumonia.


Esophageal pH monitoring using wired or wireless devices can record the pH of the lower esophagus for a period of one to several days. Impedance pH monitoring measures electrical impedance in the esophagus to evaluate reflux episodes concurrent with changes in pH. These tests are used in certain clinical indications in the evaluation of gastroesophageal reflux disease (GERD).

Gastroesophageal Reflux Disease

Acid reflux is the cause of heartburn and acid regurgitation esophagitis, which can lead to esophageal stricture. Acid reflux may also be the cause or a contributing factor in some cases of asthma, posterior laryngitis, chronic cough, dental erosions, chronic hoarseness, pharyngitis, subglottic stenosis or stricture, nocturnal choking, and recurrent pneumonia.


Gastroesophageal reflux disease (GERD) is most commonly diagnosed by clinical evaluation and treated empirically with a trial of medical management. For patients who do not respond appropriately to medications, or who have recurrent chronic symptoms, endoscopy is indicated to confirm the diagnosis and assess the severity of reflux esophagitis. In some patients, endoscopy is non-diagnostic, or results are discordant with the clinical evaluation. In these cases, further diagnostic testing may be of benefit.


Esophageal monitoring is done using a tube with a pH electrode attached to its tip, which is then passed into the esophagus to approximately 5 cm above the upper margin of the lower esophageal sphincter. The electrode is attached to a data recorder worn on a waist belt or shoulder strap. Every instance of acid reflux, as well as its duration and pH, is recorded over a 24-hour period. Wireless pH monitoring is achieved using endoscopic or manometric guidance to attach the pH measuring capsule to the esophageal mucosa using a clip. The capsule records pH levels for up to 96 hours and transmits them via radiofrequency telemetry to a receiver worn on the patient’s belt. Data from the recorder are uploaded to a computer for analysis by a nurse or doctor.

Another technology closely related to pH monitoring is impedance-pH monitoring, which incorporates pH monitoring with measurements of impedance, a method of measuring reflux of liquid or gas of any pH. Multiple electrodes are placed along the length of the esophageal catheter. The impedance pattern detected can determine the direction of flow and the substance (liquid or gas). Impedance monitoring is able to identify reflux events in which the liquid is only slightly acidic or non-acidic.


This most recent literature review was updated through September 20, 2018.

Summary of Evidence

For individuals who have GERD who receive wireless or catheter-based pH monitoring, the evidence includes cross-sectional studies evaluating test performance in different populations. Relevant outcomes are test validity, symptoms, and functional outcomes. Positive pH monitoring tests correlate with endoscopically defined GERD and with GERD symptoms, but because there is no reference standard for clinical GERD, diagnostic characteristics cannot be determined; however, these devices may aid in the diagnosis of gastroesophageal reflux disease (GERD) in patients who have an uncertain diagnosis after clinical evaluation and endoscopy. Therefore, the use of wired or wireless esophageal pH monitoring may be considered medically necessary in the patient meeting the above criteria.

For individuals who have GERD who receive impedance pH testing, the evidence includes cross-sectional studies in different populations evaluating test performance and diagnostic yield in different populations. Relevant outcomes include test validity, symptoms and functional outcomes. Positive impedance pH tests correlate with endoscopically defined GERD and with GERD symptoms, but since there is no reference standard for clinical GERD, diagnostic characteristics cannot be determined. Some studies show higher test positivity rates with impedance pH testing when compared to pH testing alone, but the effect of this finding on patient outcomes is uncertain. There are no studies of clinical utility showing improved outcomes, and the indirect chain of evidence supporting utility of the test is weak. The evidence is insufficient to determine that the technology improves health outcomes.


American College of Gastroenterology

The American College of Gastroenterology (ACG) released practice guidelines on esophageal reflux testing in 2007. The literature up to 2006 was reviewed. Although the literature on wireless pH testing was extensively reviewed, the recommendations for testing made no distinction between wireless and traditional pH monitoring. An indirect endorsement of wireless monitoring might be inferred from a statement that says that a 48-hour study would produce a greater diagnostic yield from a symptom-association test. Symptom-association tests require statistical testing of the data, and a 48-hour test produces more data points. However, these statistical correlation tests are not perfect, as the guidelines state that such measures “do not ensure a response to either medical or surgical antireflux therapies.” No studies were cited in these guidelines that indicate superior outcomes for patients for treatment guided by wireless pH testing versus traditional pH testing. The major advantage for the wireless system cited was patient tolerability.

Impedance pH monitoring was cited as “may be useful” (a lower category of recommendation than for pH monitoring) for evaluation of patients with insufficient response to medical therapy in whom documentation of nonacid reflux would alter clinical management. It was suggested that impedance monitoring has a greater yield for findings than pH monitoring when performed on PPI therapy. The last statement of the guideline states that implications of an abnormal impedance test are unproven at this time.

In 2013, ACG published guidelines on the diagnosis and management of GERD.  The guidelines indicate “ambulatory esophageal reflux monitoring is indicated before consideration of endoscopic or surgical therapy in patients with nonerosive disease, as part of the evaluation of patients’ refractory to PPI therapy, and in situations when the diagnosis of GERD is in question.” This was a strong recommendation based on a low level of evidence.  The ACG guidelines noted there is limited evidence and lack of clear consensus on how testing should be performed, e.g., catheter-based pH, wireless pH, or impedance-pH, for refractory GERD.

American Gastroenterological Association

The American Gastroenterological Association released a medical position statement and accompanying technical review on the management of GERD in 2008. Ambulatory impedance-pH, catheter pH, and wireless pH monitoring were all supported as methods to evaluate patients with suspected GERD with otherwise normal endoscopy and no response to PPI therapy. The guideline is classified as a “Grade B” recommendation, denoting fair evidence that the practice improves health outcomes. The guideline additionally states that the wireless pH monitor has superior sensitivity to catheter pH monitoring because of the extended period of recording.

National Institute for Health and Care Excellence

The National Institute for Health and Clinical Excellence (NICE) released technology appraisal guidance on catheterless esophageal pH monitoring in July 2006. This guidance indicates catheterless esophageal pH monitoring appears to be safe and effective and is commonly indicated for GERD symptoms refractory to proton pump inhibitors and for GERD symptom recurrence after antireflux surgery.

In 2015, the Institute published recommendations on the diagnosis and management of GERD in children and young people.  The recommendations specific to esophageal pH monitoring included:

“Consider performing an esophageal pH study (or combined esophageal pH and impedance monitoring if available) in infants, children and young people with:

  • suspected recurrent aspiration pneumonia
  • unexplained apneas
  • unexplained non‑epileptic seizure‑like events
  • unexplained upper airway inflammation
  • dental erosion associated with a neurodisability
  • frequent otitis media
  • a possible need for fundoplication
  • a suspected diagnosis of Sandifer’s syndrome.

Consider performing an esophageal pH study without impedance monitoring in infants, children and young people if, using clinical judgement, it is thought necessary to ensure effective acid suppression.”


Not applicable.


Ambulatory esophageal pH monitoring, gastroesophageal reflux disease (GERD), Bravo capsule, impedance pH monitoring, wireless pH monitoring, Sandhill Scientific PediaTec™ pH Probe, ORION II Ambulatory pH Recorder, TRIP CIC Catheter


Esophageal pH electrodes are considered class I devices by the U.S. Food and Drug Administration (FDA) and are exempt from 510(k) requirements. A catheter-free, temporarily implanted device (Bravo™ pH Monitoring System; Medtronic [Minneapolis, MN], now Given Imaging) was cleared for marketing by FDA through the 510(k) process for the purpose of “gastroesophageal pH measurement and monitoring of gastric reflux in adults and children from 4 years of age.”

Several wireless and catheter-based (wired) esophageal pH monitoring devices have been cleared for marketing by FDA through the 510(k) process. Examples include the Bravo™ pH Monitoring System (Given Imaging), the Sandhill Scientific PediaTec™ pH Probe (Sandhill Scientific [Highlands Ranch, CO]), the ORION II Ambulatory pH Recorder (MMS, Medical Measurement Systems [the Netherlands]), and the TRIP CIC Catheter (Tonometrics). FDA product code: FFT.


Coverage is subject to member’s specific benefits.  Group specific policy will supersede this policy when applicable.

ITS: Home Policy provisions apply

FEP contracts:  Special benefit consideration may apply.  Refer to member’s benefit plan.  FEP does not consider investigational if FDA approved and will be reviewed for medical necessity.


CPT codes:

The following CPT code is used for catheter based monitoring:


Esophagus, gastroesophageal reflux test; with nasal catheter pH electrode(s) placement, recording, analysis and interpretation

There is a specific CPT code for catheter free, wireless recording:


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

Catheter based impedance pH monitoring to test esophageal function is reported with the following CPT codes:


Esophageal function test, gastroesophageal reflux test with nasal catheter intraluminal impedance electrode(s) placement, recording, analysis and interpretation;


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)


  1. Bajbouj M, Becker V, Neuber M et al. Combined pH-metry/impedance monitoring increases the diagnostic yield in patients with atypical gastroesophageal reflux symptoms. Digestion 2007; 76(3-4):223-8.
  2. Blue Cross and Blue Shield Association Technology Evaluation Center (TEC). Special Report: Wireless pH Monitoring. TEC Assessments 2006; 21(2).
  3. Bredenoord AJ, Weusten BL, Timmer R et al. Addition of esophageal impedance monitoring to pH monitoring increases the yield of symptom association analysis in patients off PPI therapy. The Am J Gastroenterol 2006; 101(3):453-9.
  4. Garrean CP, Zhang Q, Gonsalves N et al. Acid reflux detection and symptom-reflux association using 4-day wireless pH recording combining 48-hour periods off and on PPI therapy. Am J Gastroenterol 2008; 103(7):1631-7.
  5. Grigolon A, Consonni D, Bravi I et al. Diagnostic yield of 96-h wireless pH monitoring and usefulness in patients' management. Scand J Gastroenterol 2011; 46(5):522-30.
  6. Hakanson BS, Berggren P, Granqvist S et al. Comparison of wireless 48-h (Bravo) versus traditional ambulatory 24-h esophageal pH monitoring. Scand J Gastroenterol. Dec 2009; 44(3):276-83.
  7. Hirano I, Richter JE. ACG practice guidelines: esophageal reflux testing. Am J Gastroenterol 2007; 102(3):668-85.
  8. Kahrilas PJ, Quigley EM. Clinical esophageal pH recording: a technical review for practice guideline development. Gastroenterology 1996; 110(6):1982-96.
  9. Kahrilas PJ, Shaheen NJ, Vaezi MF et al. American Gastroenterological Association Medical Position Statement on the management of gastroesophageal reflux disease. Gastroenterology 2008; 135(4):1383-91, 91 e1-5.
  10. Katz PO, Gerson LB, Vela MF. Guidelines for the diagnosis and management of gastroesophageal reflux disease. Am J Gastroenterol 2013; 108(3):308-28; quiz 29.
  11. Kessels SJM, Newton SS, Morona JK, et al. Safety and efficacy of wireless pH monitoring in patients suspected of gastroesophageal reflux disease: a systematic review. J Clin Gastroenterol. Oct 2017;51(9):777-788.
  12. Mainie I, Tutuian R, Shay S et al. Acid and non-acid reflux in patients with persistent symptoms despite acid suppressive therapy: a multicentre study using combined ambulatory impedance-pH monitoring. Gut 2006; 55(10):1398-402.
  13. National Institute for Health and Care Excellence (NICE). Gastro-oesophageal reflux disease in children and young people: diagnosis and management [NG1]. 2015; // Accessed October 28, 2018.
  14. National Institute for Health and Clinical Excellence (NICE). Catheterless esophageal pH monitoring. July 2006. Available online at: Last accessed October 28, 2018.
  15. Prakash C, Clouse RE. Value of extended recording time with wireless pH monitoring in evaluating gastroesophageal reflux disease. Clin Gastroenterol Hepatol 2005; 3(4):329-34.
  16. Ruiz D, Pinto RA, Hull TL, et al. Does the radiofrequency procedure for fecal incontinence improve quality of life and incontinence at 1-year follow-up? Dis Colon Rectum. Jul 2010;53(7):1041-1046.
  17. Scarpulla G, Camilleri S, Galante P et al. The impact of prolonged pH measurements on the diagnosis of gastroesophageal reflux disease: 4-day wireless pH studies. Am J Gastroenterol 2007; 102(12):2642-7.
  18. Schneider JH, Kramer KM, Konigsrainer A et al. Ambulatory pH: monitoring with a wireless system. Surg Endosc 2007; 21(11):2076-80.
  19. Vela MF, Camacho-Lobato L, Srinivasan R et al. Simultaneous intraesophageal impedance and pH measurement of acid and nonacid gastroesophageal reflux: effect of omeprazole. Gastroenterology 2001; 120(7):1599-606.
  20. Wenner J, Johansson J, Johnsson F et al. Optimal thresholds and discriminatory power of 48-h wireless esophageal pH monitoring in the diagnosis of GERD. Am J Gastroenterol 2007; 102(9):1862-9.


Medical Policy Group, September 2003

Medical Review Committee, September 2003

Medical Policy Administration Committee, October 2003

Available for comment October 16-December 1, 2003

Medical Policy Group, May 2004 (1)

Medical Policy Group, May 2005 (3)

Medical Policy Group, July 2006 (1)

Medical Policy Group, July 2008 (1)

Medical Policy Group, July 2010 (1) Policy statement updated for coverage of wireless pH monitoring, Key points updated

Medical Policy Administration Committee, June 2010

Available for comment June 18-August 2, 2010

Medical Policy Group, June 2011; Updated Description, Policy, Key Points, Approved by Gov. Bodies, References, and added codes from Investigational Listing 1/1/2005

Medical Policy Administration Committee, June 2011

Available for comment June 8 – July 25, 2011

Medical Policy Group, July 2012 (4): Updated Description, Policy section to add coverage for wireless and removed criteria for 48/96 hr testing, updated Key Points, References.

Medical Policy Administration Committee, July 2012.  

Available for comment July 26 through September 4, 2012

Medical Policy Panel, June 2013

Medical Policy Group, June 2013 (3): 2013 Updates to Policy, Key Points and References – policy statement wording change only – removed “24-hour” from in front of “catheter-based impedance-pH monitoring…”

Medical Policy Administration Committee July 2013

Available for comment July 12 through September 6, 2013

Medical Policy Panel, June 2014

Medical Policy Group, June 2014 (3): Updates to Key Points & References; no change in policy statement

Medical Policy Panel, June 2015

Medical Policy Group, June 2015 (4): Update to Key Points.  Moved CPT code 91299 from current coding to the previous coding section.  No change in policy statement.

Medical Policy Panel, November 2016

Medical Policy Group, November 2016 (4): Updates to Description, Key Points, and Key Words.  Removed Effective for dates of service on or after January 1, 2005 through June 12, 2013.  No changes to policy statements.

Medical Policy Panel, November 2018

Medical Policy Group, December 2018 (4): Updates to Key Points and References. Removed unlisted code 91299 from Previous Coding. No changes to policy statement or intent.  

Medical Policy Panel, November 2019

Medical Policy Group, November 2019 (5): Updates to Key Points and References. No change to Policy Statement.


This medical policy is not an authorization, certification, explanation of benefits, or a contract. Eligibility and benefits are determined on a case-by-case basis according to the terms of the member’s plan in effect as of the date services are rendered. All medical policies are based on (i) research of current medical literature and (ii) review of common medical practices in the treatment and diagnosis of disease as of the date hereof. Physicians and other providers are solely responsible for all aspects of medical care and treatment, including the type, quality, and levels of care and treatment.


This policy is intended to be used for adjudication of claims (including pre-admission certification, pre-determinations, and pre-procedure review) in Blue Cross and Blue Shield’s administration of plan contracts.

The plan does not approve or deny procedures, services, testing, or equipment for our members. Our decisions concern coverage only. The decision of whether or not to have a certain test, treatment or procedure is one made between the physician and his/her patient. The plan administers benefits based on the member’s contract and corporate medical policies. Physicians should always exercise their best medical judgment in providing the care they feel is most appropriate for their patients. Needed care should not be delayed or refused because of a coverage determination.

As a general rule, benefits are payable under health plans only in cases of medical necessity and only if services or supplies are not investigational, provided the customer group contracts have such coverage.

The following Association Technology Evaluation Criteria must be met for a service/supply to be considered for coverage:

1. The technology must have final approval from the appropriate government regulatory bodies;

2. The scientific evidence must permit conclusions concerning the effect of the technology on health outcomes;

3. The technology must improve the net health outcome;

4. The technology must be as beneficial as any established alternatives;

5. The improvement must be attainable outside the investigational setting.


Medical Necessity means that health care services (e.g., procedures, treatments, supplies, devices, equipment, facilities or drugs) that a physician, exercising prudent clinical judgment, would provide to a patient for the purpose of preventing, evaluating, diagnosing or treating an illness, injury or disease or its symptoms, and that are:

1. In accordance with generally accepted standards of medical practice; and

2. Clinically appropriate in terms of type, frequency, extent, site and duration and considered effective for the patient’s illness, injury or disease; and

3. Not primarily for the convenience of the patient, physician or other health care provider; and

4. Not more costly than an alternative service or sequence of services at least as likely to produce equivalent therapeutic or diagnostic results as to the diagnosis or treatment of that patient’s illness, injury or disease.


Esophageal pH monitoring for 24 hours using catheter-based systems is primarily used in patients with gastroesophageal reflux disease (GERD) that has not responded symptomatically to a program of medical therapy (including proton pump inhibitors [PPI]) or in patients with refractory extra-esophageal symptoms. Although it is an established technology, aspects of its use as a diagnostic test for GERD are problematic and thus make it difficult to determine its utility, as well as the utility of potential alternative tests.