Measurement of gastric emptying in man using deuterated octanoic acid

Gamma scintigraphy is considered the gold standard for the measurement of gastric emptying in humans. Recently, it has been proposed that a [(13)C]octanoate breath test can be used as an alternative technique for measuring gastric emptying of the solid phase, but the results from the two methods are not directly equivalent since in the breath test the label is subject to post-absorptive processing and consequently the emptying functions cannot be observed directly. This work investigates an alternative stable isotope method using deuterated octanoate where the kinetics of redistribution between and elimination from the various body pools are much more easily modelled. Gastric emptying was studied in healthy human volunteers by simultaneous measurement using both [(13)C]octanoate and [(2)H]octanoate as well as gamma scintigraphy. Comparison of the gastric emptying functions from the deuterium method and scintigraphy indicated that the two methods gave equivalent results. The new method can therefore be used in populations considered too vulnerable to ionising radiation to allow gamma scintigraphy to be performed, or as a proxy gold standard in laboratories where scintigraphic methods are unavailable, allowing further comparisons with the breath test method to be made to validate the latter in different population groups.