A number of sugars are used for this test. Lactulose seems to be the least specific and often has false positives.K.Title The lactulose breath hydrogen test and small intestinal bacterial overgrowth. Author Riordan SM ; McIver CJ ; Walker BM ; Duncombe VM ; Bolin TD ; Thomas MC Address Department of Gastroenterology, Prince of Wales Hospital, Sydney, Australia. Source Am J Gastroenterol, 91(9):1795-803 1996 Sep Abstract OBJECTIVES: To i) document the sensitivity and specificity of a combined scintigraphic/lactulose breath hydrogen test for small intestinal bacterial overgrowth and ii) investigate the validity of currently accepted definitions of an abnormal lactulose breath hydrogen test based on "double peaks" in breath hydrogen concentrations. METHODS: Twenty-eight subjects were investigated with culture of proximal small intestinal aspirate and a 10-g lactulose breath hydrogen test combined with scintigraphy. Gastroduodenal pH, the presence or absence of gastric bacterial overgrowth, and the in vitro capability of overgrowth flora to ferment lactulose were determined. RESULTS: Sensitivity (16.7%) and specificity (70.0%) of the lactulose breath hydrogen test alone for small intestinal bacterial overgrowth were poor. Combination with scintigraphy resulted in 100% specificity, because double peaks in serial breath hydrogen concentrations may occur as a result of lactulose fermentation by cecal bacteria. Sensitivity increased to 38.9% with scintigraphy, because a single rise in breath hydrogen concentrations, commencing before the test meal reaches the cecum, may occur in this disorder. Sensitivity remained suboptimal irrespective of the definition of small intestinal bacterial overgrowth used, the nature of the overgrowth flora, favorable luminal pH, the presence of concurrent gastric bacterial overgrowth, or the in vitro ability of the overgrowth flora to ferment lactulose. CONCLUSIONS: Definitions of an abnormal lactulose breath hydrogen test based on the occurrence of double peaks in breath hydrogen concentrations are inappropriate. Not even the addition of scintigraphy renders this test a clinically useful alternative to culture of aspirate for diagnosing small intestinal bacterial overgrowth.itle The diagnosis of small bowel bacterial overgrowth. Reliability of jejunal culture and inadequacy of breath hydrogen testing [see comments] Author Corazza GR ; Menozzi MG ; Strocchi A ; Rasciti L ; Vaira D ; Lecchini R ; Avanzini P ; Chezzi C ; Gasbarrini G Address I Department of Medical Pathology, S. Orsola University Hospital, University of Bologna, Italy. Source Gastroenterology, 98(2):302-9 1990 Feb Abstract The reliability of a single jejunal culture in the diagnosis of small bowel bacterial overgrowth has recently been questioned. Seventy-seven patients thought to have bacterial overgrowth, defined as a jejunal culture yielding at least 10(6) organisms per milliliter of aspirate, took part in the study. Bacterial overgrowth was found in 74% of the patients with predisposing conditions and in 32% of those with no clear causes of bacterial colonization. The intestinal juice of some patients was taken at two different levels of the proximal jejunum, using both the closed- and open-tube systems. Highly significant correlations (rs = 0.90, p less than 0.001) were found between the numbers of bacteria per milliliter at the 2 jejunal levels and between the numbers of bacteria per milliliter of jejunal aspirate obtained from the closed and open tubes (rs = 0.84, p less than 0.001). Compared with the jejunal culture, the gas chromatography of volatile fatty acids in jejunal aspirate and the glucose- and lactulose-hydrogen breath tests showed sensitivities of 56%, 62%, and 68% and specificities of 100%, 83%, and 44%, respectively. This work demonstrates the reliability of jejunal cultures and the inadequacy of breath hydrogen testing in the prediction of positive jejunal cultures. When results of testing for volatile fatty acids in jejunal aspirates are positive, this always indicates the presence of bacterial overgrowth; thus, this procedure would avoid the more complicated, time-consuming, and costly bacteriological analysis of jejunal samples------------------I have no financial, academic, or any other stake in any commercial product mentioned by me.My story and what worked for me in greatly easing my IBS:
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