Gastric emptying scintigraphy (GES) is usually performed for up to 2 hr to measure the gastric emptying (GE) of solids. Symptomatic patients, however, may have borderline results at 2 hr, making it difficult to determine whether a gastric motor disorder is present. The aim of this study was to assess whether extending GES to 4 hr is useful in evaluating patients for gastroparesis and to correlate the results of GES with patient symptoms. We studied 129 patients undergoing GES at Temple University Hospital between July 1998 and March 1999. Solid-phase GE was measured at 0, 0.5, 1, 2, 3, and 4 hr after ingestion of a 99mTc sulfur colloid-labeled egg meal. Dyspeptic symptoms of upper abdominal discomfort, early satiety, postprandial abdominal bloating, nausea, vomiting, and anorexia were graded as none, mild, moderate and severe (0, 1, 2 and 3, respectively) with the sum representing a total symptom score. Of 129 patients, 86 had normal GE at 2 hr; 26 of the 86 normal scans at 2 hr were delayed at 3 hr. Six of the 60 scans normal at 2 and 3 hr were delayed at 4 hr. Of 43 patients with delayed GE at 2 hr, 39 were delayed at 3 hr and 35 were delayed at 4 hr. Overall, the percentage of patients with delayed GE increased from 33% at 2 hr only to 58% using the results of the 2-, 3-, and 4-hr scans (P < 0.05). There was a significantly greater symptom score in patients with delayed GE compared to patients with normal GE (8.4 +/- 0.5 vs 7.1 +/- 0.5; P < 0.05). Conclusion, prolonging GES after ingestion of a 99mTc-labeled egg meal from 2 to 4 hr increased the number of symptomatic patients found to have delayed GE. These results suggest that GES should be performed for up to 4 hrs when the 2-hr result is normal.