Comparison between lactulose-mannitol test and 51Cr-labelled ethylene diamine tetra-acetate test in inflammatory bowel diseases.

A direct comparison was made between mannitol-lactulose and EDTA tests in 10 control subjects and in 9 and 19 patients suffering, respectively, from ulcerative colitis or Crohn's disease. The markers were orally administered in a random order and urinary recoveries were measured. At group level, significant differences were only observed in EDTA test results between control subjects and Crohn's disease patients. At the individual level, these tests exhibited poor sensitivity in ulcerative colitis, both in the inactive and active forms of the disease. In contrast, in patients suffering from Crohn's disease, the lactulose and EDTA recoveries and lactulose/mannitol ratios reached interesting figures, particularly in the EDTA 24-hr-test where 63% of the results were abnormal. This percentage climbed to 75% when active forms of the disease were selected. More interestingly, addition of abnormal results obtained with sugar and/or EDTA tests provided a significant increase in sensitivity with figures up to 90% in the entire group and 92% in patients with active forms of the disease. It is suggested that a) Neither the lactulose-mannitol test nor the EDTA test is useful in ulcerative colitis even in the active forms, b) in Crohn's disease, the sensitivity of the EDTA test is greater than that of the sugar test, c) a combination, in the same patient, of the EDTA and sugar tests is able to provide an interesting percentage of sensitivity.