Differences in Duration and Degree of Cytomegalovirus DNAemia Observed with Two Standardized Quantitative Nucleic Acid Tests and Implications for Clinical Care

Cytomegalovirus (CMV) viral loads overall were 0.29 log IU/mL higher with cobas CMV for use on the cobas 6800/8800 System (cobas CMV) compared with Cobas AmpliPrep/Cobas TaqMan CMV Test (CAP/CTM CMV). Cytomegalovirus DNAemia was detected 11.5 days earlier by cobas CMV, whereas clearance was delayed by 12.8 days. Cytomegalovirus remained detectable by cobas CMV in 44.2% of patients at the time of viral clearance as determined by CAP/CTM CMV. Undetectable viral load by cobas CMV at end of treatment was associated with reduced risk for retreatment (odds ratio, 0.26; 95% confidence interval, 0.04-0.99; P =. 05). The use of different quantitative cytomegalovirus nucleic acid tests may affect direct patient care as a result of significant differences in reporting the degree of CMV DNAemia and the time to first detection and clearance of CMV DNAemia.