Objective: To evaluate the diagnostic accuracy of a trial of a high-dose proton pump inhibitor (the omeprazole test) in detecting gastroesophageal reflux disease (GERD) in patients with heartburn symptoms.Design: A randomized, double-blind, placebocontrolled, crossover trial.Patients and Setting: Forty-three consecutive patients with symptoms suggestive of GERD were enrolled at a Veterans Affairs medical center.Main Outcome Measures: Symptom response to the omeprazole test vs placebo in GERD-positive and GERDnegative patients; sensitivity, specificity, and positive and negative predictive values of the omeprazole test; and cost per correct diagnosis achieved with the omeprazole test compared with traditional diagnostic strategies.Results: Of 42 patients (98%) who completed the study, 35 (83%) were classified as GERD positive and 7 (17%) as GERD negative. Twenty-eight GERD-positive and 3 GERD-negative patients responded to the omeprazole test, providing a sensitivity of 80.0% (95% confidence interval, 66.7%-93.3%) and a specificity of 57.1% (95% confidence interval, 20.5%-93.8%). Economic analysis revealed that the omeprazole test saves $348 per average patient evaluated, and results in a 64% reduction in the number of upper endoscopies performed and a 53% reduction in the use of pH testing. Conclusions:The omeprazole test is sensitive and fairly specific for diagnosing GERD in patients with typical GERD symptoms. This strategy could result in significant cost savings and decreased use of invasive diagnostic tests.

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