[13C-acetate breath test for the measurement of gastric emptying rates].

: Although acetaminophen (APAP) method is widely used to evaluate the gastric emptying rates of liquids in Japan, patients need to take a large dose of APAP. A scintigraphic technique requires the gamma camera. In this present state we try to search for an alternative method, which is easy to perform and noninvasive for the patient. 13C-acetate breath test and APAP method were performed at the same time in 59 patients after overnight fasting. The liquid test meal OKUNOS-A (200 ml, 200 kcal), contained APAP (20 mg/kg) and 13C-acetate 100 mg was orally administered to the patient. Breath sampling for 13CO2 measurements was obtained every 5 min up to 20 min and every 10 min up to 90 min. Blood sampling for plasma APAP concentration was collected 15, 30, 45, and 60 min after oral administration of the test meal. The time of 13CO2 peak excretion in 13C-acetate breath test was ranged from 50 to 70 min in 37 out of 59 patients. Plasma APAP concentration at 45 min in over 80 min group was significantly lower than in 50-70 min group. In contrast, that in under 40 min group was significantly higher. 13CO2 breath excretion at 30-40 min correlated with plasma APAP concentration at 45 min significantly. These results suggest that optimal sampling time of breath test is 20-40 min. In conclusion, 13C-acetate breath test is reliable as a qualitative analysis, easy to perform, and a noninvasive method without taking blood and radiation exposure for a measurement of gastric emptying rates.