Fecal pH test

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Fecal pH test
Synonymsfaecal pH test, stool acidity test

A fecal pH test is one where a specimen of feces is tested for acidity in order to diagnose a medical condition. The pH of human feces is variable but usually alkaline.[1] An acidic stool can indicate a digestive problem such as lactose intolerance,[1] an infection such as E. coli or rotavirus, or overgrowth of acid-producing bacteria (such as lactic acid bacteria).

The average pH for a healthy person is 6.6.[2]

Test procedure[edit]

The test is fast and can be performed in a doctor's office. A patient must not be receiving antibiotics. At least half a milliliter of feces is collected, and a strip of nitrazine paper is dipped in the sample and compared against a color scale. A pH of less than 5.5 indicates an acidic sample.[3]


Unhealthy individuals with a higher or lower pH rate have been observed having a higher mortality rate. A high alkaline pH rating is associated with the body's inability to create enough acid along with undigested food.[4]


  1. ^ a b "Point-of-Care Testing, Fecal pH Measurement". Archived from the original on 2007-07-03. Retrieved 2007-02-07.
  2. ^ "010991: Stool pH". Health Matters. Retrieved 2023-07-06.
  3. ^ "eMedicine - Gastroenteritis, Bacterial : Article by Jennifer Lynn Bonheur, MD".
  4. ^ Osuka A, Shimizu K, Ogura H, Tasaki O, Hamasaki T, Asahara T, Nomoto K, Morotomi M, Kuwagata Y, Shimazu T (July 2012). "Prognostic impact of fecal pH in critically ill patients". Critical Care. 16 (4): R119. doi:10.1186/cc11413. PMC 3580696. PMID 22776285.

See also[edit]