Construction and Evaluation of Cytomegalovirus DNA Quantification System with Real-Time Detection Polymerase Chain Reaction

BACKGROUND For patients with reactivation of human cytomegalovirus (CMV), a highly sensitive and accurate CMV quantification system is essential to monitor viral load. METHODS We constructed a real-time detection PCR (RTD-PCR) system for CMV DNA and evaluated its linearity, lower detection limit, dynamic range and accuracy using two CMV standards. We used 219 clinical samples derived from 101 patients to compare the system with the pp65 antigen test. RESULTS The 95% detection limit was determined to be 556 IU/mL (95% CI, 440-797 IU/mL), and the quantification range was between 102 and 106 copies or IU/mL (r = 0.996, 0.999, respectively). The coefficients of variation of inter-assay reproducibility assessed in each three different runs were 2.5% at 1,000 IU/mL and 1.6% at 10,000 IU/mL. The coefficients of variation of intra-assay variability by testing the same samples three times in a single run were 1.8-3.6% and 0.4-1.9%, respectively. The concordance between antigenemia and plasma or serum CMV DNA levels was a good correlation (r = 0.695, P < 0.01). CONCLUSION We constructed the RTD-PCR system which enables accurate evaluation of CMV reactivation by monitoring of viral load in immunosuppressed or immunocompromised patients.