The Centers for Disease Control and Prevention is urging clinical labs to use bacterial cultures of stool specimens in suspected cases of Escherichia coli O157:H7 infection to facilitate diagnosis and proper control measures.

Failure to culture specimens can cause labs to mistake some other pathogen for E coli O157:H7, leading to inappropriate public health measures, the CDC says.

There have been recent reports of false positive test results stemming from clinical labs that use enzyme immunoassay to look for the toxins created by E. coli.