Agreement between 3-hour and 24-hour rapid urease test readings for detection of Helicobacter pylori infection

Abstract

Introduction: The rapid urease test (RUT) is a widely used, inexpensive method for detecting Helicobacter pylori (H. pylori) infection during upper gastrointestinal endoscopy. Although manufacturers recommend reading results at 24 hours, many tests turn positive earlier. Delayed reading beyond 24 hours may yield false-positive results due to non-H. pylori bacterial urease activity. This study aimed to determine the agreement between 3-hour and 24-hour RUT readings.

Method: A prospective cross-sectional agreement study was conducted at the endoscopy unit of Patan Hospital, Patan Academy of Health Sciences, Nepal. Adults aged 18 years or older undergoing upper gastrointestinal endoscopy with biopsy for RUT were included. A single antral biopsy was placed in a commercially available RUT kit. Readings were recorded at 3 hours and 24 hours. Agreement was assessed using Cohen’s kappa statistic.

Result: A total of 124 patients were enrolled. At 3 hours, 38 patients tested positive and 86 tested negative. At 24 hours, 41 patients were positive and 83 were negative. Three patients were negative at 3 hours but turned positive at 24 hours. No patient was positive at 3 hours but negative at 24 hours. Cohen’s kappa was 0.94 (95% CI), indicating almost perfect agreement.

Conclusion: The 3-hour RUT reading demonstrates almost perfect agreement with the standard 24-hour reading. Early reading at 3 hours can facilitate same-day clinical decision-making and timely initiation of eradication therapy in most patients.