The urine Indican test (also called the Obermeyer test) is an indirect laboratory method for the diagnosis of intestinal dysbiosis and microbial overgrowth in the small intestine (SIBO). Indican is a by-product (indole) produced when bacteria in the gut act on the amino acid tryptophan. Most of the produced indoles are excreted in the feces, while a very small amount of these substances are absorbed in the intestine, metabolized in the liver, and excreted as indican in the urine.
Normally, only a very small amount of indican is detected in the urine. The amount of indican in the urine increases when a high protein diet is followed or when inefficient digestion of proteins takes place. When proteins are not sufficiently assimilated by the body, bacteria metabolize them in the large intestine with the simultaneous production of indoles. Then, these indoles are absorbed and converted in the liver to indican.
Patients with an increased level of urinary indican usually eat poorly or drink a lot of alcohol or live a stressful life. Elevated levels of indican may also indicate indigestion and hypochlorhydria (stomach dysfunction). Indican excretion is reduced when the intestine is colonized with beneficial bacterial strains while the higher the level of colonization with good bacteria, the lower the level of indican in the urine.
Although the urine Indican test is not a specific method for the detection of intestinal Candidiasis, most patients who develop a clinical picture of Candidiasis are positive in the Indican test.