Urinary Indican/Obermeyers
This is indicated when putrefaction or bacterial overgrowth in the digestive tract is suspected.
The human body is host to a vast arrays of microorganisms that breakdown a variety of substances into their component parts. There has been a considerable amount of interest in determining what effects these breakdown products have on human health. Foe example, there is evidence that a tryptophan metabolite is implicated in the development of autism.
Obermeyers test measures one of these breakdown products called indican. Indicate is formed by putrefactive bacteria, which use tryptophanases to metabolize tryptophan into indo. Absorbed into the portal circulation, indole is conjugated to sulfur in the liver resulting in indican, which is then excreted into the urine. The indican test can be used clinically to identify patients with putrefactive bacterial flora capable of metabolizing amino acids such as tryptophan. Two components are needed: bacteria capable of producing indole (E. coli, Bacteroides, Klebsiella) and the other is a protein source to be metabolized. The bacteria may be present in the small intestine in cases of small bowel overgrowth syndrome, small intestine diverticula, or small bowel blind loop to name a few. The bacterial flora of the large intestine may also harbour putrefactive bacteria resulting in indole production when sufficient protein is available to metabolize.
Elevated indican has been found in individuals with increased bacterial colony counts from human jejunum, however a number of negative colony counts have also been found with high indican levels. This suggests that a postive indican test is not specific for overgrowth of bacteria in the small intestine, and may be due to the presence of undigested protein in the large intestine. Remember the presence of indican indicated putrefaction of protein by bacteria in the digestive tract. It is in the skills of the doctor to determine if the cause is from malabsorption, bowel contents stasis, maldigestion, etc. Below are some conditions associated with elevated indican:
- Inflammatory bowel disease
- Hypochlorhydria
- Gastric ulcer
- Biliary and intestinal obstruction
- Jejunal diverticulosis
- Scleroderma
- Post-gastrectomy
- Hartnup’s disease (impaired tryptophan absorption)
- Pancreatic insufficiency
- Diminished peristalsis
- Blue diaper syndrome