Fecal pH 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. An acidic stool can indicate a digestive problem such as lactose intolerance, 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 has a reference range of 7.0 to 7.5. Test procedure. 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. Results. 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.