Comparison of Six Real-Time PCR Assays for Qualitative Detection of Cytomegalovirus in Clinical Specimens

In this study, we compared the performance of six real-time PCR assays for the qualitative detection of cytomegalovirus (CMV) in clinical samples other than plasma. Two hundred specimens (respiratory [n = 72], urine [n = 67], cerebrospinal fluid [CSF] [n = 25], tissue [n = 18], amniotic fluid [n = 10], and bone marrow [n = 8]) submitted for routine testing by CMV real-time PCR analyte-specific reagents (ASR) (Roche Diagnostics, Indianapolis, IN) were also tested by a laboratory-developed test (LDT) and 4 commercially available PCR assays: EraGen Multicode (Luminex, Austin, TX), Focus Simplexa (Focus Diagnostics, Cypress, CA), Elitech MGB Alert CMV (Fisher Scientific, Hanover Park, IL), and Abbott CMV (Abbott Park, IL). Nucleic acid was extracted using the MagNA Pure system (Roche Diagnostics) and subsequently tested by each PCR method. Results were analyzed by comparing each assay to a "consensus result," which was defined as the result obtained from at least 4 of the 6 assays. In addition to the prospective samples, 13 lower respiratory samples with known positive results by CMV shell vial were tested by each PCR method. Following testing of the 200 prospective specimens, the Abbott, Elitech, EraGen, and Focus PCR assays demonstrated a sensitivity of 100% (46/46), while the Roche analyte-specific reagents (ASR) and LDT showed sensitivities of 89% (41/46) and 98% (45/46), respectively. Percent specificities ranged from 97% (149/154) by Elitech to 100% (154/154) by the LDT. Among the 13 shell vial-positive lower respiratory samples, the percent sensitivities ranged from 69% (9/13) by Elitech to 92% (12/13) by the LDT. The Abbott, EraGen, Elitech, Focus, and LDT PCR assays performed similarly (kappa >= 0.89) for the detection of CMV in clinical specimens and demonstrated increased sensitivity compared to the Roche ASR.