Cytomegalovirus quantification in plasma with Abbott RealTime CMV and Roche Cobas Amplicor CMV assays

We assessed the performance of Abbott RealTime CMV assay (ARC) compared to Roche Cobas Amplicor CMV Monitor Test (RCM) for quantification of CMV in plasma of transplant patients. Commercial panels were used to test linearity, precision and interference and 83 clinical samples were used for the accuracy and precision analyses. All 43 RCM-positive clinical samples tested positive by ARC. The overall concordance between the two tests was good (98%). Based on 17 samples, the inter-assay median coefficient of variation was 13%. A linearity panel ranging from approximately 1 to 7log10copies/mL was used to confirm linearity (R(2)=0.99). CMV viral load measurement was not affected by different concentrations of HSV-1 or EBV DNA. We conclude that The Abbott RealTime CMV assay offers good sensitivity, precision and linearity and is suitable for monitoring CMV viral loads in transplant recipients. Standardization with the WHO CMV standard allows for comparison with other assays.