Seroprevalence of Hepatitis E Virus Infection among Blood Donors in Lebanon: A National Comparative Evaluation of Two Serological Assays

Hepatitis E virus (HEV) is an emerging transfusion-transmissible pathogen, yet epidemiological data from the Middle East remain limited, and differences in serological assay performance complicate interpretation of seroprevalence. Lebanon lacks national HEV surveillance data and has no blood donor screening policy. In this cross-sectional national study, 3000 blood donors from all Lebanese governorates (July 2023-August 2024) were screened for anti-HEV IgG and IgM using two commercial platforms: Euroimmun ELISA and Roche Elecsys electrochemiluminescence immunoassay (ECLIA). This study represents the first large-scale, peer-reviewed evaluation of the Roche Elecsys Anti-HEV assays in a national blood donor population. All samples that were positive or borderline by either serological assay were tested for HEV RNA using real-time RT-PCR (Altona RealStar® and Roche Cobas®). Anti-HEV IgG seroprevalence differed significantly between assays (Euroimmun: 1.13% vs. Roche Elecsys: 1.93%; p < 0.001). IgM prevalence was 0.07% and 0.33%, respectively. Overall agreement between assays was high (IgG: 98.7%; IgM: 99.7%), although Cohen's κ indicated limited concordance, with Roche Elecsys identifying additional low-reactivity seropositive donors. Seropositivity varied across regions, with higher rates observed in South Lebanon (4.0%) and North Lebanon (3.1%). HEV RNA was not detected in any tested donor. HEV exposure among Lebanese blood donors is low but geographically distributed. Seroprevalence estimates were strongly assay-dependent, indicating that HEV burden may be underestimated when lower-sensitivity platforms are used. These findings highlight the importance of assay selection in HEV epidemiological studies and support consideration of selective HEV nucleic acid testing for high-risk recipients to inform evidence-based blood safety policy in Lebanon.