Multicenter comparison of laboratory performance in cytomegalovirus and Epstein-Barr virus viral load testing using international standards.

Background Infections with cytomegalovirus (CMV) and Epstein Barr Virus (EBV) remain important in solid organ transplantation. Quantitative viral nucleic acid testing is a major advance to patient management. These assays are limited by a lack of standardization, resulting in viral load measurements that differ among clinical laboratories. The variability in viral load measurements makes interpretation of multicenter clinical trials data difficult. This study compares the current practices in CMV and EBV viral load testing at four large transplant centers participating in multicenter Clinical Trials in Organ Transplantation (CTOT/CTOTC).