Evaluation of a quantitative enzyme-linked immunosorbent assay for feline leukemia virus p27 antigen and comparison to proviral DNA loads by real-time polymerase chain reaction

[Display omitted] •FeLV proviral DNA loads have been shown to correlate with stage of infection.•This study evaluated a quantitative ELISA for FeLV p27 antigen.•p27 antigen concentration had a positive correlation with proviral DNA loads.•Quantifying antigen may help to stage progressive and regressive infections. Feline leukemia virus (FeLV) is an oncogenic retrovirus of cats. While higher viral RNA and proviral DNA loads have been correlated with progressive infections and disease, a similar correlation has been suggested for p27 antigen concentrations. This analytical study compared the results of a quantitative ELISA for p27 antigen with quantitative real-time PCR results for FeLV proviral DNA in patient samples. A significant positive correlation between copies of proviral DNA and the concentration of p27 antigen was identified (r = 0.761, P