Background: In the absence of highly specific symptoms and without eso
phageal erosions, long-term pH monitoring is necessary for diagnosing
gastroesophageal reflux disease. This method, however, is not generall
y available. Objective: To determine whether gastroesophageal reflux d
isease can be diagnosed empirically by acid suppression in patients wi
th normal results of endoscopy. Methods: We studied 33 consecutive out
patients with pathologic findings on pH monitoring who had symptoms co
mpatible with gastroesophageal reflux disease and normal results of es
ophagogastroduodenoscopy, particularly a normal appearance of the esop
hageal mucosa. The severity of symptoms was graded on a visual analog
scale from 1 to 10 by the patient. The patients were treated for at le
ast 7 days with either ranitidine, 150 mg twice daily (patients 1 thro
ugh 10), omeprazole, 40 mg/d (patients 11 through 21), or omeprazole,
40 mg twice daily (patients 22 through 33). A reassessment of symptoms
and second pH monitoring were performed during the last day of treatm
ent. Results: Omeprazole, 40 mg/d, significantly reduced the severity
of symptoms from 7.1 (range, 4 to 9) to 3.7 (0 to 8) and the reflux me
asure mean acidity from 0.98 mmol/L (0.21 to 76 mmol/L) to 0.02 mmol/L
(0 to 0.47 mmol/L). Omeprazole, 40 mg twice daily, significantly redu
ced the severity of symptoms from 6.8 (3 to 10) to 0.6 (0 to 2) and th
e mean acidity from 0.38 mmol/L (0.13 to 8.5 mmol/L) to 0.01 mmol/L (0
to 0.14 mmol/L). Both doses of omeprazole were superior to ranitidine
, 150 mg twice daily. When a 75% reduction of symptoms was defined as
positive, the ''omeprazole test'' with 40 mg twice daily had a sensiti
vity of 83.3%, whereas the sensitivity with 40 mg/d was only 27.2%. Co
nclusion: In practice, the diagnosis of gastroesophageal reflux diseas
e can be ruled out if symptoms do not improve with a limited course of
high-dose proton pump inhibitors.