BACKGROUND: Mpox has spread to 36 countries in Africa, yet many face challenges achieving nationwide PCR-based testing due to cost and limited access in remote and rural areas. Point-of-care antigen-based rapid diagnostic tests (RDTs) might help improve diagnostic access. The aim of this study was to evaluate the diagnostic accuracy of five mpox antigen-based RDTs. METHODS: We performed a retrospective diagnostic accuracy study using lesion swabs from patients from a WHO transmission study with suspected mpox in nine health zones of Kinshasa province in DR Congo from Feb 12 to June 28, 2025, supplemented by PCR-negative swabs from consenting patients from other research studies. Five antigen-based RDTs were assessed, with results compared against the RADI FAST Mpox PCR assay. The parent study took swabs from people of all ages with suspected and probable case infection who presented to health-care facilities, as well as those within the community or in households. For each participant, six lesion swabs were collected: one was used for reference testing and each remaining swab was used for a different RDT. The primary outcome of diagnostic accuracy, as measured by sensitivity and specificity in tests from all patients, was assessed in DR Congo by operators masked to the results of other assays. Analytical sensitivity was evaluated using MPXV clade Ib isolates at the Geneva University Hospitals (Geneva, Switzerland). FINDINGS: We tested lesion swabs from 190 patients (153 from the WHO transmission study and 37 additional patients). The best performing assay, from Guangdong Wesail Biotech, had a sensitivity of 77·3% (95% CI 68·0-84·5; 75 of 97) and specificity of 93·5% (86·6-97·0; 87 of 93). The Hangzhou Testsea Biotechnology assay had a similar performance (sensitivity 72·2% 62·5-80·1; 70 of 97); specificity 93·5% 86·6-97·0; 87 of 93). Tests with moderate sensitivity and high specificity were by Beijing Hotgen Biotech (sensitivity 59·8% 49·8-69·0; 58 of 97; specificity 96·8% 90·9-98·9; 90 of 93) and Contipharma (sensitivity 50·5% 40·7-60·3; 49 of 97; specificity 95·7% 89·5-98·3; 89 of 93). The NG Biotech assay had the lowest sensitivity (39·2% 30·1-49·1; 38 of 97) but a similarly high specificity (96·8% 90·9-98·9; 90 of 93). INTERPRETATION: Several antigen-based RDTs show high positive predictive values for mpox screening in high-prevalence settings, in which positive test results could support confirmation of infection in the absence of PCR but negative results cannot rule out infection. FUNDING: Ministry of Health, Labour, and Welfare of the Government of Japan.
Kavunga-Membo et al. (Fri,) studied this question.