Comparison of Roche and Abbott Cytomegalovirus Quantitative PCR Assays in Allogeneic Hematopoetic Cell Transplant Recipients

BACKGROUND: Human Cytomegalovirus (CMV) infection is prevalent in patients undergoing transplantion (Tx) and carries significant morbidity and mortality. Quantification of CMV viremia has improved with the use of standardized international units and new commercial real time PCR assays. This study compares the current Roche cobas AmpliPrep/cobas TaqMan CMV test (TM assay) and Abbott Molecular RealTime CMV Investigational Use Only assay (ART assay) for quantification of CMV viremia in patients receiving allogeneic hematopoietic stem cell transplants (aHSCT). METHODS: Prospective CMV positive patients, planned for aHSCT, were consented prior to Tx and followed weekly up 12 weeks post-transplant (PT) and once ~3 months PT. Matched paired plasma samples were processed and analyzed per manufacturer instructions, Henry Ford clinical laboratory processed the samples using the TM assay and the McKinnon Research Laboratory processed the paired samples using the ART assay. Parametric and non-parametric analyses were conducted as appropriate. RESULTS: Fourteen patients enrolled, 1 patient withdrew after entering, 1 patient died after 9 weeks PT (primary disease). Patients received peripheral blood stem cells and 84.6% received myeloablative chemotherapy. In paired samples, quantifiable CMV by TM and ART assays was detected in 6 (5 treated) vs. 8 of 13 patients respectively. ART assay detected CMV in all patients with positive paired samples, 1 detected in an unpaired sample and in 2 patients missed by TM assay (P = 0.021). Assays also differed in samples with no detection, detectable and quantifiable CMV viremia, with more frequent detection in the ART assay (P = 0.009). Time to quantifiable viremia PT by TM and ART assays was a median of 5 vs. 3 weeks (P = 0.026). Bland-Altman plot shows higher viremia levels quantified using the ART assay (P = 0.023). After week 4 PT, ART assay results inversely correlated with platelets counts (P = 0.013). CMV viremia tended to persist 1.9 weeks longer using ART vs.. TM assay (P = 0.07). CONCLUSION: CMV viremia was quantified earlier, at higher levels and persisted in patients with aHSCT using the ART assay compared with the TM assay. Further study is warranted to determine clinical impact of ART assay on the management of CMV viremia. DISCLOSURES: J. Mckinnon, Abbott Molecular: Speaker’s Bureau, Grant recipient and Speaker honorarium D. Lucic, Abbott Molecular: Employee, Salary