Detection of cytomegalovirus by the early-antigen immunofluorescence test versus conventional tissue culture.

The two methods commonly used to diagnose cytomegalovirus (CMV) infections, conventional tissue culture and detection of early CMV nuclear antigen by immunofluorescence from cell culture, were performed in parallel on 597 clinical specimens. CMV was detected by the early-antigen test in 108 samples, of which 102 (94%) were detected 1 to 3 days after inoculation. Of these 108 CMV-positive specimens, seven were negative on conventional culture. Two samples negative in the early-antigen test were positive on conventional culture. Thus, CMV was detected in 110 specimens. A cytopathic effect in conventional tissue culture occurred 9 to 42 days after inoculation. The diagnosis of CMV infection was possible by the conventional method 29.6 +/- 12.7 days and by early-antigen immunofluorescence 1.9 +/- 1.5 days after obtaining the specimen. The rapid early-antigen test was slightly more sensitive than culture, and fewer samples were lost due to bacterial or fungal infections during incubation. Detection of CMV by conventional culture usually requires several weeks and provides a diagnosis only retrospectively. The main advantage of the early-antigen test is that a virologically proven diagnosis of CMV infection is available at an early stage.