Alternative and simpler methods to identify active HCMV replication could be a valuable improvement in monitoring transplanted patients and guiding therapy, particularly in patients receiving LTV. In the past years, the determination of viral transcripts in whole blood for monitoring HCMV replication has been proposed [5-7]. Recently, an assay targeting virion-associated UL21.5 mRNA, a late transcript that is highly expressed and packaged into virions during lytic infection [8], has been developed.