[13C]octanoic acid breath test for gastric emptying of solids: accuracy, reproducibility, and comparison with scintigraphy.
OBJECTIVE
Previous work suggested that a breath test using 13C accurately measures gastric emptying of solids. Thus, breath test half emptying time (t1/2) minus 66 minutes was claimed to estimate accurately t1/2 by scintigraphy. The aim of this study was to evaluate the accuracy and reproducibility of this breath test in healthy subjects.


METHODS
Fifteen volunteers (8 men and 7 women; mean age, 41 +/- 13 years) underwent simultaneous scintigraphy and [13C]octanoic acid breath test. Scans and breath samples were obtained every 15 minutes for 4 and 6 hours, respectively. The breath test was repeated three times within a 3-week period.


RESULTS
Parameters from scintigraphy and breath test were not correlated significantly. Differences of lag phase and t1/2 between the two tests were highly variable (range for t1/2, -33.1 to 169.6; mean, 48.0 minutes). Increasing breath test "duration" (samples over 4, 5, or 6 hours) yielded decreasing estimates of the lag phase and t1/2. Although widely different values were observed in some subjects, repeated breath tests showed a high degree of reproducibility within individuals (mean coefficient of variation, 12%).


CONCLUSIONS
[13C]Octanoic acid breath test for gastric emptying of solids requires further validation before it can substitute for scintigraphy as a diagnostic test, but it seems useful for intraindividual comparisons.
Choi
M G
MG
Gastroenterology Research Unit, Mayo Clinic and Mayo Foundation, Rochester, Minnesota 55905, USA.
Camilleri
M
M
Burton
D D
DD
Zinsmeister
A R
AR
Forstrom
L A
LA
Nair
K S
KS
D000328:Adult; D000368:Aged; D001944:Breath Tests; D002210:Caprylates; D002247:Carbon Isotopes; D005069:Evaluation Studies as Topic; D005260:Female; D005746:Gastric Emptying; D006801:Humans; D008297:Male; D008875:Middle Aged; D011877:Radionuclide Imaging; D015203:Reproducibility of Results; D013270:Stomach / Q000000981:diagnostic imaging*
D002210:Caprylates; D002247:Carbon Isotopes; C031492:octanoic acid