A retrospective comparative diagnostic evaluation of three commercial qPCR kits for the diagnosis of mpox virus on an enriched sample set.

Mpox virus (MPXV) is an enveloped double-stranded DNA virus belonging to the genus Orthopoxvirus within the family Poxviridae. It causes a zoonotic disease transmitted to humans through direct contact with infected animals or humans, as well as through exposure to contaminated materials. The aim of this study was to conduct a retrospective, comparative diagnostic evaluation of three commercial real-time PCR (qPCR) kits for the diagnosis of MPXV on an enriched, artificially balanced sample set that included 50% MPXV-positive samples. World Health Organization (WHO) reference molecular protocol was used as the reference comparator. A total of 300 clinical specimens, 150 of them MPXV-positive (265 skin lesion/vesicle swabs and 35 serum samples), were used in this analysis. The Bioperfectus kit correctly identified 294/300 samples, showing a sensitivity of 0.96 (95% CI: 0.93-0.99), a specificity of 1.00 (0.98-1.00), and a Cohen's Kappa coefficient of 0.96 (95% CI: 0.92-0.99), with an overall agreement of 0.98 (0.96-0.99). The VIASURE kit correctly detected 293/300 specimens, yielding a sensitivity of 0.95 (0.92-0.99), specificity of 1.00 (0.98-1.00), Cohen's Kappa coefficient of 0.95 (95% CI: 0.92-0.99 and an overall agreement of 0.98 (0.95-0.99). The Singuway kit showed the highest concordance with the reference method, correctly classifying 295/300 samples and presenting a sensitivity of 0.97 (0.94-1.00), specificity of 1.00 (0.98-1.00), Cohen's Kappa coefficient of 0.97 (95% CI: 0.94-1.00), with an overall agreement of 0.98 (0.97-1.00). This study demonstrates a good sensitivity and specificity, and strong overall agreement among the three commercial kits compared to the WHO protocol. Nevertheless, further analysis using unbiased clinical sample sets that reflect the true prevalence of MPXV-positive samples is needed for a real-world clinical performance evaluation.