- Performance of the TechLab C. DIFF CHEK-60 enzyme immunoassay (EIA) in combination with the C. difficile Tox A/B II EIA kit, the Triage C. difficile panel immunoassay, and a cytotoxin assay for diagnosis of Clostridium difficile-associated diarrhea. Snell, H., Ramos, M., Longo, S., John, M., Hussain, Z. J. Clin. Microbiol. (2004)