AbstractBackgroundMany diagnostic tests for gastroduodenal symptoms, such as gastric emptying scintigraphy (GES), gastric emptying breath tests (GEBT), and electrogastrography (EGG) show variable intra‐individual reproducibility over time. This study investigated the short‐ and long‐term reproducibility of body surface gastric mapping (BSGM), a non‐invasive test for assessing gastric function, in controls and patients with chronic gastroduodenal disorders.MethodsParticipants completed three standardized BSGM tests using Gastric Alimetry® (Alimetry, New Zealand). The test encompassed a fasting baseline (30 min), a 482 kCal standard meal, and a 4 h postprandial recording. The first two tests were >6 months apart and the last occurred ~1 week after the second test, to evaluate long and short‐term reproducibility.ResultsFourteen patients with upper gastrointestinal symptoms and 14 healthy controls were recruited. There were no significant differences in any BSGM metrics between the tests at short and long term (all p > 0.180). Lin's concordance correlation coefficients (CCC) for the primary metrics were high, ranging from 0.58 to 0.96, with intra‐individual coefficients of variance (CV_intra) ranging from 0.2% to 1.9%. Reproducibility was higher, and intra‐individual variation lower, than in previous studies of GES (CCC = 0.54–0.83, CV_intra = 3%–77%), GEBT (CV_intra = 8%–11%), and EGG (CV_intra = 3%–78%).ConclusionsBSGM spectral metrics demonstrate high reproducibility and low intra‐individual variation at both short and long term, with superior results to comparable tests. The high reproducibility of Gastric Alimetry supports its role as a diagnostic aid for gastric dysfunction and a reliable tool for evaluating treatment outcomes and disease progression over time.