Diagnosis of Giardia and Cryptosporidium Infection in Children with Diarrheal Illness Using Rapid Immunochromato- graphic Assay

Background: Giardia and Cryptosporidium are both enteric pathogens causing diarrhea with no reliable method for their diagnosis. The aim of our study was to evaluate the diagnostic performance of a rapid immunochromatographic (IC) ImmunoCard STAT! Crypt/Giardia assay (Meridian Bioscience, Inc.) in comparison to composite reference standard (CRS) of both wet mount microscopy and ELISA copro-antigen assay in the diagnosis of both pathogens. Methods and Findings: One hundred twenty two children complaining of chronic diarrhea were checked for infection by Giardia and Cryptosporidium using wet mount microscopy, ELISA copro-antigen assay and the rapid IC test. The rapid assay had a sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPP) and diagnostic accuracy (DA) of 89, 100, 100, 94% and 96% for Giardia and 78, 100, 100, 98 and 98% for Cryptosporidium in reference to CRS. Conclusions: The rapid IC assay proved to be simple, time-saving and objective; it can be used as a rapid screening test for giardiasis and cryptosporidiosis or integrated with other diagnostic modalities to confirm diagnosis.