Performance of an In-House Real-Time PCR Assay for Detecting Cytomegalovirus Infection among Transplant Patients from a Tertiary Care Centre

Abstract

Background: Quantitative Cytomegalovirus (CMV) polymerase chain reactions are increasingly being used for monitoring CMV DNAemia in haematopoietic stem cell transplants and solid organ transplants. Objective: In this study, a commercial CMV viral load assay was compared with an in-house viral load assay. Materials and Methods: A total of 176 whole-blood samples were tested for CMV DNAemia using both assays. Results: Our evaluation showed a difference of 1 log10 copies/ml between the two assay systems in determining CMV viral loads in the clinical samples. Conclusion: The in-house viral load assay had a better correlation with clinical findings compared to the commercial assay. Quality assessment of these assays was done by the United Kingdom National External Quality Assessment Scheme (UKNEQAS), an external proficiency testing programme, and by the National Institute for Biological Standard and Control (NIBSC) standard. For UKNEQAS and NIBSC standards, the bias between the assays was 0.73 log10 and 0.85 log10, respectively. This difference is well within the acceptable range already reported in the literature.