Comparison of seven enzyme immunoassay systems for measurement of cytomegalovirus

The relative sensitivities of seven different enzyme immunoassay (EIA) systems for the measurement of cytomegalovirus (CMV) were compared. Methods which used two separate antisera to CMV provided the greatest degree of sensitivity. Equivalent sensitivity was noted with the use of either enzyme-labeled antiglobulin or unlabeled staphylococcal protein A and rabbit enzyme-antienzyme complex to measure the second anti-CMV antibody bound to the solid phase. Single-antibody methods were less sensitive than the double-antibody methods but were more sensitive than an inhibition EIA. However, the sensitivity of the inhibition EIA was improved when CMV-antibody complexes were separated from unreacted antibody by means of precipitation with polyethylene glycol. Double-antibody EIA systems are preferable when antisera prepared in two different animal species are obtainable. However, a number of single-antibody EIA systems can be formulated for use in situations where only a single antiserum is available.