Evaluation of the diagnostic accuracy and analytical sensitivity of the novel Xpert Mpox (Cepheid) and STANDARD M10 MPX/OPX (SD Biosensor) molecular point-of-care assays for the detection of Mpox virus in skin lesion swabs and upper-respiratory swab samples

Objectives Evaluation of diagnostic accuracy of two point-of-care (POC) molecular diagnostic tests for the detection of monkeypox virus (MPXV): Xpert Mpox (Cepheid, Inc., USA) and STANDARD M10 MPX/OPX (SD Biosensor, Inc., Korea). Methods Diagnostic accuracy of both platforms was evaluated using 53 upper-respiratory swabs (URS) and 32 skin lesions swabs (SS) collected from mpox and COVID-19 patients in the UK against the Sansure (Sansure Biotech Inc.) and the CDC reference qPCR tests. The analytical sensitivity of both platforms was assessed using a viral isolate from the lineage II, B.1. Results The limit of detection was 1x101 pfu/ml for both tests. The overall sensitivity and specificity of the Xpert Mpox was 97.67% [95% CI 87.71-99.94%] and 88.57% [95% CI 73.26-96.80%] and 97.44% [95% CI 86.52-99.94%] and 74.42% [95% CI 58.83-86.48%] comparing the Sansure and CDC qPCR, respectively and for the M10 MPX/OPX was 87.80% [95% CI 73.80-95.92%] and 76.60% [95% CI 61.97-87.70%] and 94.29% [95% CI 80.84-99.30%] and 86.67% [95% CI 73.21-94.95%] with the Sansure and CDC qPCR. Conclusion The Xpert Mpox had good diagnostic accuracy for both sample types while the M10 MPX/OPX clinical accuracy was deficient with URS. Our data supports the use of URS during the first 3 days of symptoms onset for mpox diagnosis.