Comparison of complement fixation and fluorescent immunoassay (FIAX) for measuring antibodies to cytomegalovirus and herpes simplex virus.

An automated fluorescent immunoassay system (FIAX) was compared with complement fixation (CF) for measuring antibodies to cytomegalovirus (CMV) and herpes simplex virus (HSV) in clinical specimens. Compared with CF the specificity of FIAX (ability to detect a negative titer) was 95% for CMV and 92% for HSV. The sensitivity of FIAX (ability to detect a positive titer) was 98% for CMV and 95% for HSV. When paired samples were tested for significant titer rises, the concordance of the two assays for CMV was 96% and for HSV 80%. The FIAX assay was found to be reproducible when sera were tested within the same laboratory and in two different laboratories. The assay is fast, simple to perform, and not affected by anticomplementary activity. It is seen as a useful alternative to CF testing in a clinical virology laboratory.