The serologic diagnosis of viral infection. An update.

The traditional basis for the serologic diagnosis of a viral infection is demonstration of seroconversion or a significant increase in circulating homologous viral antibody over the course of illness. Conventional methods include neutralization, complement fixation, hemagglutination-inhibition, indirect hemagglutination, and indirect immunofluorescence tests. Although these methods are reliable, each suffers from limitations that include procedural complexity, substantial "hands-on" time, need for titrating reagents and serially diluting specimens, occasional false-positive or false-negative results, and lack of interlaboratory standardization. Because of these problems, improved methods and new techniques for serologic diagnosis have been developed and investigated. Many appear to be superior to conventional methods in sensitivity, specificity, cost, time required for completion, and potential for automation. The advent of hybridoma technology has provided an exceptional opportunity to improve serologic reagents for the diagnosis of viral disease. In addition, IgM-specific antibody tests for rapid and early diagnosis of many viral infections are being reevaluated to eliminate the interfering effects of rheumatoid factor and antinuclear antibodies. Many of the new methodologies employ immunofluorescence assay or enzyme immunoassay for detection of specific IgM antibody, and latex agglutination, in addition to immunofluorescence and enzyme immunoassays, to detect specific IgG antibody. Simplified kits employing these methods are now becoming available commercially.