[Measurement of ileal absorption of bile salts with the selenium 75 labelled homotaurocholic acid test. Validation and clinical significance]

Abstract

Objectives and methods: The performances and the clinical significance of a simplified version of the 75SeHCAT test which measures ileal absorption of bile salts were assessed in 23 healthy subjects and 106 patients. Corporeal retention of the marker was measured using an uncollimated gamma-camera.

Results: In healthy subjects, the 75SeHCAT retention was lower in the group of 9 with an osmotic diarrhoea induced by a PEG solution than in the group of 14 tested in normal conditions (22 +/- 4% vs 44 +/- 4%; P < 0.01). The reproducibility of the measure was good (r = 0.93; P < 0.001). The sensibility and specificity of the test for the diagnosis of ileal involvement were 79% and 90% respectively. Bile acid malabsorption was evidenced in 38% of patients with functional diarrhoea (59% and 28% in patients with and without previous cholecystectomy respectively; P < 0.02). In patients with fonctional diarrhoea, a correlation was evidenced between the orofaecal transit time and the 75SeHCAT retention (r = 0.66; P < 0.001) and cholestyramine improved diarrhoea in 8 out of 11 patients with 75SeHCAT malabsorption and in 2 out of 5 patients with normal test. These results show that the 75SeHCAT test is accurate and that bile acid malabsorption, frequently evidenced in functional diarrhoea, is correlated with an acceleration of intestinal transit.