Enzyme immunoassays for the detection of microbial antigens and prospects for improved assays

The rapid diagnosis of viral infections is an important tool in the management of patients with infectious diseases. Solid-phase enzyme immunoassays have proved to be useful tools for the direct detection of the antigens of some viruses directly in clinical specimens. Such assays have been particularly useful in the diagnosis of viral infections in the gastrointestinal and respiratory tracts. However, standard solid-phase enzyme immunoassays often do not display sufficient sensitivity for the diagnosis of all cases of viral infections. Techniques which might be utilized to increase the sensitivity of solid-phase immunoassays include the use of monoclonal antibodies to maximize the efficiency of the antigen-antibody interactions and the use of high-turnover enzymes to increase the amount of signal generated by the ensuing enzyme-substrate reactions. In addition, techniques making use of nucleic acid hybridization have a great deal of potential for the accurate detection of viral nucleic acids in human body fluids. The successful application of these techniques to the diagnosis of viral infections could lead to a marked improvement in the care of patients with suspected infectious diseases as well as to a decrease in the transmission of viral infections to high-risk individuals.