Evaluation of the Merifluor immunofluorescent assay for the detection of Cryptosporidium and Giardia in sodium acetate formalin-fixed stools.

The Merifluor Cryptosporidium/Giardia direct immunofluorescent assay (MFDFA) was used for the blinded detection of Cryptosporidium and Giardia in 100 previously tested sodium acetate formalin (SAF)-preserved fecal specimens. Examination for ova and parasites by formalin-ether concentration followed by iron-hematoxylin and Kinyon staining had demonstrated Cryptosporidium (n = 32), Giardia (n = 20) and both Giardia and Cryptosporidium (n = 5). The MFDFA detected one additional specimen with Cryptosporidium and another with Giardia and was rapid, accurate, and simple to perform.