Molecular diagnosis of Cytomegalovirus infection: clinical performance of Transcription Mediated Amplification (TMA) towards conventional qPCR chemistry on whole blood samples.

Human Cytomegalovirus (HCMV) infection represents a life-threating pathogen for immunocompromised patients. Molecular quantitative testing on whole blood or plasma represents the gold standard for diagnosis of invasive HCMV infection and for monitoring antiviral treatment in individuals at risk of CMV disease. For these reasons, accurate standardization towards the 1st WHO International standard between different centres and diagnostic kits represent an effort for a better clinical management of CMV-positive patients. Herein, we evaluate for the first time the performance of a new TMA (Transcription Mediated Amplification) kit towards qPCR chemistry, used as routine method, on whole blood samples. 755 clinical whole blood specimens were collected and simultaneously tested with TMA and qPCR assays. Data showed 99.27% agreement for positive quantified samples and 89.39% agreement for those not detected between two tested methods. Evaluation of viraemia in positive samples highlighted a good correlation for TMA and qPCR chemistries in terms of International Units ({Delta}Log10 IU/ml: - 0.29 {+/-} 0.40). TMA assay showed a significant correlation with qPCR also in monitored patients until three months, thus allowing accurate evaluation of viraemia in transplanted patients. Moreover, preliminary data about analytical sensitivity of TMA chemistry onto DBS samples showed 86.54% correlation with whole blood specimens. Thus, TMA chemistry showed a good agreement with qPCR assay, used as current diagnostic routine, and offers important advantages: FDA and IVD approval on plasma and whole blood, automated workflow with minimal hands-on time, random access loading, thus enabling a rapid and reliable diagnostics in HCMV-infected patients.