Comparison of an enzyme immunoassay with electron microscopic procedures for detecting rotavirus

The sensitivity and specificity of an enzyme immunoassay (Rotazyme), an ongrid immunoelectron microscopy procedure, and conventional negative stain electron microscopic techniques were compared. By using partially purified human rotavirus and simian rotavirus (SA-11) of known particle concentration, the enzyme immunoassay was essentially equivalent to the immunoelectron microscopic procedure and significantly more sensitive than conventional electron microscopic techniques. The level of sensitivity was approximately 10(6) particles per ml for simian rotavirus SA-11 and 10(7) particles per ml for human rotavirus. In an evaluation of 455 clinical samples by these techniques, a sensitivity of 98% and specificity of 92% were demonstrated. Samples negative by the immunoelectron microscopic procedure and positive by enzyme immunoassay could be confirmed by a blocking assay.