Validation of the lactose-[13C]ureide breath test for determination of orocecal transit time by scintigraphy.
The breath test using oral administration of a 13C-labeled substrate, lactose-ureide (LU), to measure orocecal transit time (OCTT) was validated against 99mTc-scintigraphy. Although LU is not absorbed in the human small intestine, colonic bacteria readily metabolize LU, producing 13C-labeled CO2. The time at which 13CO2 appears in breath corresponds to the OCTT.


METHODS
Twenty-two healthy volunteers ingested a meal labeled with 99mTc and 13C-LU. Scintigraphy was performed over 8 h at time intervals of 10 or 15 min. OCTT with scintigraphy was defined as the time at which at least 10% of the label had entered the colon. Breath samples were obtained every 10-15 min for 10 h and measured by isotope ratio mass spectrometry. OCTT was defined as the time of first significant increase above baseline. The results were compared using correlation and Altman-Bland statistics.


RESULTS
OCTT results from scintigraphy (mean OCTT = 283+/-53 min) and breath test (mean OCTT = 292+/-58 min) correlated well (r = 0.94). Altman-Bland statistics showed close agreement between scintigraphy and breath test. No significant difference between male and female subjects was observed.


CONCLUSIONS
The breath test using 13C-LU is a valid alternative to scintigraphy techniques for measuring OCTT.
Geypens
B
B
Center for Gastrointestinal Research, KU Leuven, Belgium.
Bennink
R
R
Peeters
M
M
Evenepoel
P
P
Mortelmans
L
L
Maes
B
B
Ghoos
Y
Y
Rutgeerts
P
P
D000328:Adult; D001944:Breath Tests; D002432:Cecum / Q000502:physiology; D004064:Digestive System / Q000000981:diagnostic imaging; D005260:Female; D005772:Gastrointestinal Transit; D006801:Humans; D008297:Male; D013058:Mass Spectrometry; D008875:Middle Aged; D009055:Mouth; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D013671:Technetium Tc 99m Sulfur Colloid
D019275:Radiopharmaceuticals; D013671:Technetium Tc 99m Sulfur Colloid