[The 13C-acetate Breath Test for the Noninvasive Assessment of the Gastric Emptying of a Liquid/solid Test Meal in Diabetics]

Objective: To test in a prospective study whether the non-invasive 13C-acetate test is suitable for measuring gastric emptying time with a liquid/solid test meal. (99m)technetium scintigraphy served as the reference method.

Patients And Methods: 18 consecutive type 2 diabetics with symptoms of gastroparesis (nine men, nine women; mean age 64 [45-76] years) were, after a nocturnal fasting period, given a liquid/solid test meal (370 kcal; 100 ml coffee; doubly marked with 75 mg 13C-acetate and 0.5 mCi 99mTc-colloid). At ten-minute intervals breath samples were taken over two hours and examined by mass spectometry for the 13CO2/12CO2 ratio. In parallel scintigraphy was performed for one hour at one-minute intervals. Gastric emptying half-life (t1/2) was calculated and the correlation between the two methods determined. In addition, the 13C-acetate breath test was performed on 20 healthy subjects to assess reproducibility (ten men, ten women; mean age 44.4 [23-77] years).

Results: Median t1/2 with the scintigraphy was 93.5 min, with the breath test 55 min, i.e. a significant correlation (r = 0.8; P < 0.001). Four of five patients with delayed gastric emptying by scintigraphy also showed delay (compared with the control group) in the breath test (median t1/2: 41 min; 95th percentile: 86 min).

Conclusion: The 13C-acetate test correlated significantly with the results by scintigraphy. It can therefore be recommended as a non-invasive test for assessing gastric emptying time after a liquid/solid test meal in type 2 diabetics.