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How Long Should a pH Probe Last to Accurately Diagnose Gastroesophageal Reflux

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RI Rusu et al. Clin Gastroenterol Hepatol 2026; 24: 365-374. Open Access! The Optimal Duration of pH Monitoring: Testing the Validity of Lyon 2.0 Recommendations for Wireless pH Measurement

Background: “The Lyon 2.0 consensus recommends 96-hour wireless pH studies for gastroesophageal reflux disease (GERD) diagnosis…Ninety-six-hour monitoring is not always possible, either for technical reasons (eg, early detachment of the pH sensor) or for practical and financial reasons (48-hour studies are routine and cost-efficient in many centers).”

Methods: Data from 944 patients (16-85 years) with 4-day recordings (Bravo capsule) was reviewed. Patients were classified at 24, 48, and 72 hours against the 96-hour reference standard. Acid exposure time (AET) <4% was conclusively negative, and AET >6% was conclusively positive for GERD.

Key findings:

  • With longer duration, more patients were able to be diagnosed with GERD and fewer patients were in the indeterminate group. The proportion of patients with inconclusive results (AET 4%–6%) reduced from 113 of 944 at 24 hours to 40 of 113 at 96 hours (35% of subgroup; P = .02)
  • Only 3 of 60 patients with LA grade B esophagitis demonstrated physiologic reflux burden across all 96 hours of recording (which indicates that for significant reflux esophagitis, pH monitoring is not needed in most cases)
  • In the associated editorial (pg 306-308), the authors note that “the minimum duration for an effective study seems to be 3 days, because ~90% of conclusively positive studies identified over 4 days would be detected with 72 hours of recording. However, to achieve this, a 4-day study would need to be planned because of potential data loss, reported in almost a third of the cases in this and prior cohorts.”
  • “96-hour wireless monitoring is optimal for ruling out GERD when the pretest likelihood of reflux is low, especially when empiric PPI therapy is ineffective.”

My take: pH probe tests have many limitations. This study reinforces the need for longer studies in many patients when the findings would be equivocal with shorter duration studies.

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