Diagnosis of cytomegalovirus infection.

The diagnosis of cytomegalovirus (CMV) infection in bone marrow transplant recipients is most accurately accomplished by the identification of CMV in the organ of concern; identification of CMV in bronchoalveolar lavage fluid can also be helpful in diagnosing CMV interstitial pneumonia. When tissue specimens are available, the identification of cytomegalic cells is often helpful in establishing CMV as the pathogen. Immunocytochemistry and in situ hybridization can increase the sensitivity and specificity of the CMV diagnosis; when nonisotopic detection systems are used, each can be performed the same day the specimen is obtained. Direct viral culture can also be used to establish a diagnosis. Although culture of CMV on human fibroblasts is still considered the diagnostic "gold standard," identification of the virus in culture may take several days to several weeks. The use of the shell-vial viral culture procedure, in conjunction with monoclonal antibodies directed at immediate early CMV antigens, has made it possible to detect CMV in culture within 24 hours. The use of nucleic acid hybridization procedures, including amplification of CMV sequences by the polymerase chain reaction, is highly sensitive; however, the application of these hybridization procedures to the diagnosis of CMV disease remains unclear.