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Am J Gastroenterol. 1998 Jan;93(1):92-8.

Reproducibility and simplification of 13C-octanoic acid breath test for gastric emptying of solids.

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Mass Spectrometry Core Laboratory, Mayo Clinic and Mayo Foundation, Rochester, Minnesota 55905, USA.



The accuracy of the 13C-octanoic acid breath test is enhanced by breath sampling over 6 h rather than 4 h, but this increases the cost of the test. Our aim was to validate a less costly but accurate sequence of breath sampling for measuring gastric emptying of solids.


We performed the 13C-octanoic acid breath test and tested its reproducibility relative to simultaneous scintigraphy in 30 healthy volunteers.


There was a significant but weak correlation between t1/2 measured by the two tests (rs = 0.54, p < 0.005), but not between the duration of the lag phase. The differences in the t1/2 measurements between the tests were different between subjects but were highly reproducible within subjects. Within- and between-subject variations of measurements of gastric emptying with the 13C-octanoic acid breath test were not significantly different from the variations observed with scintigraphy. A subset of 11 breath samples collected over 6 h (24 samples) predicted (r2 > 0.95) the variables characterizing the cumulative appearance of 13CO2 in breath; these samples were at 35, 50, 95, 110, 140, 155, 215, 245, 260, 290, and 335 min. The accuracy of this subset of sampling times was confirmed in a separate set of breath test samples over 6 h from the same 30 subjects.


The 13C-octanoic acid breath test for gastric emptying of solids is as reproducible as scintigraphy. A subset of 11 sampling times provides sufficient information to characterize the whole breath-test curve, but the sampling period should be extended to 6 h after dosing.

[Indexed for MEDLINE]

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