Vincent Jeanne Perpétue auteur aut IRD Ségéral O. auteur aut IRD Kania D. auteur aut IRD Borand L. auteur aut IRD Adoukara J. P. auteur aut IRD Pivert A. auteur aut IRD Koné A. auteur aut IRD Tiendrebeogo A. S. E. auteur aut IRD Tall H. auteur aut IRD Schaeffer L. auteur aut IRD Vray M. auteur aut IRD Sanou A. M. auteur aut IRD Njouom R. auteur aut IRD Cloherty G. auteur aut IRD Hashimoto N. auteur aut IRD Miura T. auteur aut IRD Sugiura W. auteur aut IRD Sovann S. auteur aut IRD Yang J. S. auteur aut IRD Delvallez G. auteur aut IRD Lunel-Fabiani F. auteur aut IRD Tanaka Y. auteur aut IRD Shimakawa Y. auteur aut IRD text journalArticle eng text/pdf reformatted digital access Background Timely administration of the hepatitis B virus (HBV) birth dose vaccine, along with identifying high-risk pregnant individuals for antiviral prophylaxis, is essential for the global elimination of vertical transmission of HBV. However, in resource-limited settings, access to HBV DNA testing is scarce, and accurate rapid tests for HBeAg are lacking. We aimed to assess the diagnostic performance of a newly developed hepatitis B core-related antigen (HBcrAg) rapid diagnostic test (RDT) to identify women who are HBsAg-positive and eligible for antiviral prophylaxis. Methods In this multicountry diagnostic accuracy study, we retrospectively validated the HBcrAg-RDT using stored plasma from pregnant women who were HBsAg-positive in cohort studies from Cambodia and Cameroon and prospectively using finger-prick capillary blood from postpartum mothers at rural health centres in Burkina Faso. We estimated the sensitivity and specificity of the HBcrAg-RDT for diagnosing high HBV DNA concentrations (>= 200 000 IU/mL) using real-time PCR (rtPCR) as the reference. We compared the diagnostic performance of the HBcrAg-RDT with that of conventional HBeAg assays based on the area under the receiver operating characteristic curve (AUROC). Findings In total, plasma samples were available for 1964 participants: 1194 stored plasma samples available for analysis from the Cambodian cohort, 501 stored samples from the Cameroonian cohort, and 269 prospectively collected samples from women in the Burkina Faso cohort. In the pooled population, the mean age was 28<middle dot>1 years (SD 6<middle dot>0), and 382 (20<middle dot>0%) were HBeAg positive. The HBcrAg-RDT showed an overall sensitivity of 93<middle dot>1% (95% CI 90<middle dot>5-95<middle dot>2) and specificity of 94<middle dot>3% (93<middle dot>0-95<middle dot>4). Sensitivity and specificity were 93<middle dot>4% (90<middle dot>7-95<middle dot>5) and 94<middle dot>4% (92<middle dot>9-95<middle dot>6) in the retrospective laboratory-based analyses of samples from Cambodia and Cameroon, and 89<middle dot>7% (75<middle dot>8-97<middle dot>1) and 93<middle dot>9% (90<middle dot>0-96<middle dot>6) in the prospective real-world analysis of samples of HBsAg-positive women from Burkina Faso. The AUROC for HBcrAg-RDT (0<middle dot>937 [95% CI 0<middle dot>924-0<middle dot>950]) in distinguishing high versus low HBV DNA concentrations at the 200 000 IU/mL threshold in the pooled data set was significantly higher than that of HBeAg rapid tests (0<middle dot>822 [0<middle dot>798-0<middle dot>845]; p<0<middle dot>0001) and similar to laboratory-based HBeAg immunoassays (ELISA and chemiluminescence assay; 0<middle dot>926 [0<middle dot>897-0<middle dot>955]; p=0<middle dot>72). In Burkina Faso, the median turnaround time for HBV DNA testing was 46 days (IQR 31-72), whereas HBcrAg-RDT provided same-day results for all participants. Interpretation HBcrAg-RDT might offer a practical solution for integrating the prevention of vertical transmission of HBV into decentralised antenatal care in resource-limited settings, enabling timely identification and management of pregnant individuals who are at high risk of transmission. specialized CAMBODGE CAMEROUN BURKINA FASO 050 052 10 5 452-461 2025 https://www.documentation.ird.fr/hor/fdi:010093456 10.1016/s2468-1253(25)00015-9 [F B010093456] https://www.documentation.ird.fr/hor/fdi:010093456 https://horizon.documentation.ird.fr/exl-doc/pleins_textes/2025-06/010093456.pdf IRD - Base Horizon / Pleins textes 2025-06-11 2025-11-04 fdi:010093456 fre