Clinical evaluation of a fully automated CMV PCR assay

BackgroundThere is a growing need for sensitive high-throughput cytomegalovirus (CMV) PCR tests due to the increasing number of immunocompromised patients requiring monitoring for active CMV infection.ObjectivesTo compare the fully automated COBAS^® AmpliPrep/COBAS^® TaqMan^® (CAP/CTM) CMV test (this test is currently under development and not commercially available) for EDTA–plasma to the reference method COBAS^® AMPLICOR CMV MONITOR.Study designA prospective feasibility study with parallel analysis of 433 EDTA–plasma samples from 277 patients on both systems was carried out after the analytical performance of the new system had been assessed.ResultsThe new system has a wide linear range from 2.0 to 7.3 log₁₀ CMV-DNA copies/ml EDTA–plasma and a detection limit of 46 copies/ml with excellent accuracy and precision. When testing clinical samples, the CAP/CTM CMV test compared extremely well with the COBAS^® AMPLICOR CMV MONITOR (R² = 0.93, p < 0.001) with increased sensitivity and linear range. Discrepant samples all contained low titers of CMV-DNA. In two of the study patients, CMV-DNAemia was detected by the CAP/CTM CMV test up to eight weeks earlier than by COBAS^® AMPLICOR CMV MONITOR.ConclusionAn IVD/CE marked version of the CAP/CTM CMV test will enable laboratories to provide a sensitive, fully automated high-throughput CMV PCR.