Collaborative national multicenter for the identification of conversion factors from copies/mL to international units/mL for the normalization of HCMV DNA load

Francesca Sidoti, Antonio Piralla, Cristina Costa, Maria Luisa Scarasciulli, Agata Calvario, Pier Giulio Conaldi, Pierpaolo Paba, Carlo Federico Perno, Aurelia Gaeta, Guido Antonelli, Giuseppe Sodano, Rosaria Santangelo, Maurizio Sanguinetti, Maria Linda Vatteroni, Luisa Barzon, Giorgio Palù, Isabella Abbate, Maria Rosaria Capobianchi, Giulia Piccirilli, Tiziana LazzarottoFausto Baldanti, Rossana Cavallo

Research output: Contribution to journalArticle


The present multicentric (n = 11 laboratories) study aimed to identify conversion factors from copies/mL to international units (IU)/mL for the normalization of HCMV DNA load using the first WHO International Standard for HCMV nucleic acid amplification techniques and to enhance interlaboratory agreement of HCMV DNA quantification methods. Study protocols for whole blood and plasma (extraction and amplification) were performed to calculate conversion factors from HCMV DNA copy number to IU. The greatest variability was observed in samples with lower HCMV concentrations (3.0 Log10) in both biological matrices. Overall, 73.1% (206/282) of whole blood and 82.2% (324/394) of plasma samples analyzed fell within an acceptable variation range (±0.5 Log10 difference). An average of 0.64 (range 0.21–1.17) was the conversion factor calculated for the HCMV whole blood panel and 0.82 (range 0.39–2.2) for the HCMV plasma panel.

Original languageEnglish
JournalDiagnostic Microbiology and Infectious Disease
Publication statusPublished - Jan 1 2019



  • HCMV
  • International standard
  • Multicenter study

ASJC Scopus subject areas

  • Microbiology (medical)
  • Infectious Diseases

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