Comprehensive assessment of gastric emptying with a stable isotope breath test

Background The [C-13]-Spirulina platensis gastric emptying breath test (GEBT) with five samples is accurate relative to scintigraphy. This study was primarily designed to further validate this GEBT using a slightly different process for incorporating [C-13] in Spirulina and to evaluate the utility of additional samples for assessing early gastric emptying. Methods After a 223 kcal, test meal labeled with Tc-99m and [C-13]-S. platensis, scintigraphic images, and five breath samples (45, 90, 120, 180, and 240 min, GEBT5) were collected in 14 controls (Part A). In Part B, nine breath samples were collected at 15, 30, 45, 60, 90, 120, 150, 180, and 240 min (GEBT9) in 30 subjects (15 controls, 15 dyspepsia). Using correlation between [C-13] breath excretion and scintigraphic emptying, lag time (t(10), time for 10% emptying), emptying at 30 min (GE(30)), and half time (t(50)) were estimated for GEBT5 (Parts A and B) and GEBT9 (Part B). Key Results Half time values for scintigraphy, GEBT5, and GEBT9 were highly concordant. t(10) by GEBT9 (90%CI, 6-15 min) was more strongly correlated [CCC 0.80 (95% CI, 0.63-0.90)] with scintigraphy (90% CI, 5-12 min), than GEBT5 [10-19 min, CCC 0.73 (95% CI, 0.54-0.85)]. The correlation between estimated values (GEBT9) and linearly interpolated values (GEBT5) was closer at 60 [CCC 0.95 (95% CI, 0.91-0.97)] than 30 min [CCC 0.81 (95% CI, 0.71-0.89)]. Conclusions & Inferences The [C-13]-S. platensis GEBT can accurately measure GE. While 5- and 9-samples are equally accurate for measuring t(50), GEBT9 provides a more comprehensive assessment of early GE (t(10) and GE(30)).