Clinical Application
As most of the endogenous indoles have a side chain which prevents cleavage and are instead metabolized to skatole, the production of indicans (indoxyl potassium sulfate and indoxyl glucoronate) reflects bacterial activity in the small and large intestines. The table below lists conditions in which increased levels are found. Elevated levels are considered as an indicator of intestinal toxemia and overgrowth of anaerobic bacteria.

Conditions with Elevated Levels of Urinary Indican

• Inflammatory bowel disease
   
• Celiac disease
   
• Hypochlorhydria (low levels of Hydrochloric Acid)
   
• Achlorhydria ( no production of Hydrochloric acid)
   
• Gastric ulcer
   
• Biliary and intestinal obstruction
   
• Jejunal diverticulosis
   
• Scleroderma
   
• Postgastrectomy
   
• Hartnup's disease
   
• Pancreatic insufficiency
   
• Diminished peristalsis
   
• Blue diaper syndrome
   
• Hypermotility of the small intestine
   

Procedure
Detection of indicans depends upon its decomposition to indoxyl and subsequent oxidation to indigo blue. It is then concentrated into a layer of chloroform for easier measurement.

Results

Interpretation
A positive test may indicate one of the diseases listed in table 1, hypochlorhydria, bacterial overgrowth in the small and/or large intestine, maldigestion and/or malabsorption of protein.

References
1. Todd J: Clinical Diagnosis and Management by Laboratory Methods. WB Saunders, Phil, Pa 1979. pp 592-3
2. Greenberger N, Saegh S, and Ruppert R: Urine indican excretion in malabsorption disorders. Gastroenterol 55:204-11, 1968
3. Curzon G and Walsh J: Value of measuring urinary indicant excretion. Gut 7:711, 1966
4. Asatoor A, London D, Craske J, and Milne M: Indole production in Hartnup's disease. Lancet i:126-8, 1963