Comparative sensitivity of eight- and 24-hour bile acid breath tests and Schilling test in ileopathies.

The conventional eight-hour bile acid breath test ("acute measurements"), was compared with a modified, extended, 24-hour breath test ("ratio measurements") and the Schilling test to assess relative sensitivity in detecting ileal dysfunction. Sixty-four patients with ileopathies were studied. The presence or absence of bile acid malabsorption was documented by fecal excretion studies of bile acid labels. The sensitivity of the "acute measurements" in the breath test was not significantly different from that of the "ratio measurements" in the ileopathies, regardless of whether or not bile acid malabsorption was present. The "acute measurements" were positive in 49 (77%), the "ratio measurements" in 54 (84%) and the Schilling test in 49 (77%) of the patients. In about 30%, bile acid breath test and Schilling test were not positive in the same patient. A combination of "acute measurements" (breath test) and Schilling test increased the percentage of cases with at least one positive test to 91%. The results of the study show: 1. The sensitivity of the bile acid breath test does not increase if 14CO2 measurements are carried out beyond eight hours. 2. Although the breath test and Schilling test are of similar sensitivity in ileopathies, they are frequently not positive in the same patient. Therefore, it would be clinically useful to combine both tests in order to increase the likelihood of diagnosing ileal dysfunction.