Table 1.

Summary of conventional techniques used for detection of HCMV infection in different specimens.

Method	Specimens	Comments
Serology	Blood	The presence of IgG determines that a patient has had HCMV infection in the past and is considered a carrier of latent virus. Detection of IgM without detectable IgG indicates acute primary infection, while detection of both IgM and IgG indicates reactivated HCMV infection.
Antigenemia	Blood	Use of monoclonal antibodies to detect the presence of HCMV pp65 in neutrophils during the early period of the virus replication cycle. Reported as number of pp65-positive cells per number of neutrophils counted. Sensitive but limited by the lack of automation, assay standardization and subjective interpretation.
Cell culture	Blood, Urine, Saliva	Conventional approach where clinical specimens are inoculated onto human fibroblasts, incubated and observed over time. Takes 2–21 days for reporting a result based on a morphological analysis. It is possible to obtain a faster detection of HCMV in culture already 24 h post-infection by using staining with anti-IE antibodies. Highly specific but low sensitivity for HCMV infection.
Polymerase Chain Reaction	Blood, Urine, Saliva, Tissue	Rapid and sensitive method based on amplification of nucleic acids. Targets even low levels of immediate early and late genes or transcripts. Quantitative nucleic acid amplification guides preemptive strategies, monitors response to therapy and is the preferred method for diagnosis of HCMV infection.
Immunohistochemical Staining	Blood, Urine, Saliva, Tissue	Monoclonal or polyclonal antibodies are applied against various HCMV proteins and visualized by dye or fluorescently labelled antibodies or enzyme/polymer labelled secondary antibodies, allowing morphological identification of HCMV in the specimen. It is a highly sensitive and very specific technique. Considered goldstandard for diagnosis in HCMV end-organ diseases.