Urinary Indican

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Latest Edit: Hector 2014-03-21 (EDT)

See Also Lab Tests

The urine Indican test, also called an Obermeyer test, is an indicator of intestinal toxemia and overgrowth of anaerobic bacteria. Indican is an indole produced when bacteria in the intestine act on the amino acid, tryptophan. Most indoles are excreted in the feces. The remainder is absorbed, metabolized by the liver, and excreted as indican in the urine.

Normally, only a small amount of indican is found in the urine. The amount of urine indican increases with high protein diets or inefficient protein digestion. If protein is not digested adequately, bacteria act on the protein causing putrefaction in the colon and the production of indoles, which are absorbed and converted in the liver to Indican. Following absorption, indole is converted to 3-hydroxy indole (indoxyl potassium sulfate and indoxyl glucuronate), which are termed indicans, in the liver.


Conditions that lead to excess urine Indican include:[1], [2]

  • Maldigestion and/or malabsorption of protein
  • Bacterial overgrowth in the small and/or large intestine

Patient Preparation

  • No special patient preparation required, yet a meal with some protein to ensure adequate amounts of tryptophan (required for an accurate test result) should be eaten the night before the sample is taken.
  • Avoid alcohol 24 hrs before taking urine sample may produce a false negative result.
  • Kelp & other supplements (e.g Bladderwrack herbal tincture) high in iodine should be avoided for three days before taking urine sample.
  • If the assay is not run immediately, place sample in labeled plastic tube and freeze.
  • Collect your first urine specimen of the morning, mid-stream in the clean specimen container. It is important to use first morning urine as indican levels can reduce throughout the day.
  • Testing and review of results takes approximately 15 mins.
  • Detection of indican in the urine is based on the colour change. The presence of indican depends upon its decomposition and subsequent oxidation of indoxyl to indigo blue and its absorption into a chloroform layer. The resulting color is visually compared to a color chart and graded as follows:
Urinary Indican
Rating Colour
Negative (Normal) Clear or blue tinge
1+ {Slightly Positive) Slight blue, yellow, mint green
2+ (Positive) Dark blue, light green, golden brown
3+ (High Positive) Violet, indigo, dark brown
4+ (Very High Positive) Jet black


  1. Greenberger N, Saegh S, and Ruppert R. Urine indican excretion in malabsorption disorders. Gastroenterol 1968;55:204-11. PMID: 4385691.
  2. Patney NL, Mehrotra MP, Khanna HK, Kumar A. Urinary indican excretion in cirrhosis of liver. J Assoc Physicians India. 1976 May;24(5):291-5. PMID: 1022761.
  3. Patney NL, Saxena SK, Mehrotra MP, Khanna HK, Kumar A. Urinary indican in diabetes mellitus. J Indian Med Assoc. 1977 Mar 1;68(5):94-7. PMID: 903638.