Centrifugation-augmented solid-phase immunoassay (CASPIA) for the rapid diagnosis of infectious diseases.

We have devised centrifugation-augmented solid-phase immunoassays (CASPIAs) for the detection of microbial pathogens in human body fluids. The CASPIA format combines several features of latex agglutination and solid-phase immunoassay systems to produce an assay system that is inexpensive and simple to perform. We found that CASPIA systems for the detection of rotaviral, group A streptococcal, and Haemophilus influenzae type b antigens were significantly more sensitive than latex agglutination assays and at least as sensitive as enzyme immunoassay systems using analogous reagents. Because CASPIA reactions could either be read macroscopically, recorded with a standard office photocopying device, or quantitated by means of a microplate colorimeter, the assays were applicable under a wide range of clinical and laboratory conditions.