Editing Lactose intolerance (section)

=== Stool acidity test ===
This test can be used to diagnose lactose intolerance in infants, for whom other forms of testing are risky or impractical.<ref>{{cite web |author=National Digestive Diseases Information Clearinghouse |title=Lactose Intolerance&nbsp;— How is lactose intolerance diagnosed? |url=http://digestive.niddk.nih.gov/ddiseases/pubs/lactoseintolerance/#diagnosed |date=March 2006 |publisher=National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health |url-status=dead |archive-url=https://web.archive.org/web/20111125192619/http://digestive.niddk.nih.gov/ddiseases/pubs/lactoseintolerance/#diagnosed |archive-date=2011-11-25 |access-date=2004-11-19 }}</ref> The infant is given lactose to drink. If the individual is tolerant, the lactose is digested and absorbed in the small intestine; otherwise, it is not digested and absorbed, and it reaches the colon. The bacteria in the colon, mixed with the lactose, cause acidity in stools. Stools passed after the ingestion of the lactose are tested for level of acidity. If the stools are acidic, the infant is intolerant to lactose.<ref>{{cite web|title=Stool Acidity Test|url=http://www.medicinenet.com/stool_acidity_test/article.htm#stool|publisher=Jay W. Marks, M.D.|access-date=2011-05-20|url-status=live|archive-url=https://web.archive.org/web/20110516210041/http://www.medicinenet.com/stool_acidity_test/article.htm#stool|archive-date=2011-05-16}}</ref>
Stool pH in lactose intolerance is less than 5.5.