THE URSODEOXYCHOLIC ACID P-AMINOBENZOIC ACID DECONJUGATION TEST, A NEW TOOL FOR THE DIAGNOSIS OF BACTERIAL OVERGROWTH SYNDROME

Objective: To determine the possible complementary role of the ursodeo xycholic acid-p-aminobenzoic acid (UDCA-PABA) loading test in the diag nosis of intestinal bacterial overgrowth. Design: A prospective clinic al study. Patients and methods: The hydrogen breath and UDCA-PABA test s were performed simultaneously in 68 patients with suspected contamin ated small bowel syndrome (CSBS), and in 10 healthy control subjects. The hydrogen breath test was performed by oral loading of 25g of lacto se and/or 10g of lactulose. The UDCA-PABA test was carried out by oral loading of 250 mg of UDCA-PABA conjugate, followed by measurement of the amount of PABA excreted in the urine. The diagnosis of bacterial o vergrowth was considered to be established when either the hydrogen br eath test or the UDCA-PABA test produced abnormal results. Results: Th irty-five of the 68 patients proved to have CSBS. In 13 of these 35 pa tients, only the enhanced urinary PABA excretion (11.7 +/- 1.42 mg vs. 3.6 +/- 0.68 mg) indicated bacterial overgrowth, 15 of the 35 patient s gave only a positive hydrogen breath test, and in the remaining seve n cases the results of both tests were abnormal. In eight CSBS patient s, the urinary excretion of PABA was decreased significantly following 10-day tinidazole treatment (5.5 +/- 1.29 mg vs. 13.1 +/- 2.07 mg). C onclusion: The UDCA-PABA lest is a valuable clinical method for the de tection of bacterial overgrowth, especially in cases where hydrogen pr oduction alone fails to reveal CSBS. It is also a useful procedure for evaluating the efficacy of antibacterial treatment.