Laboratory Personnel, Slide 8
Hippurate Test (Rapid Hippurate Test)
This test is an additional presumptive test used to aid in the identification of GBS. It is a variation of the hippurate hydrolysis test. Hippurate (hippuric acid) is a benzene (6 carbon) ring with the amino acid serine attached to one of the carbon molecules. Hippuricase, the enzyme, cleaves the benzene ring and the serine free from each other. In this case, some of the growth on a blood agar plate is suspended in a solution of hippurate and incubated for 4 hours. Next, a reagent ninhydrin is added. If a purple color develops, in the tube, the test is positive. The test detects the amino acid serine that has been cleaved from the hippuric acid. The second tube is positive for hippurate hemolysis and presumptive identification of GBS.
Page Last Modified: April 20, 2008
Content Last Reviewed: April 20, 2008
Content Source: National Center for Immunization and Respiratory Diseases