Development of a broadly adaptable TR-FRET serological assay for sensitive and specific detection of infectious disease antibodies in human sera

Abstract

Detecting antibodies (Abs) is essential for assessing acquired immunity to infectious diseases, particularly following vaccination or prior infection. However, conventional serological tests often suffer from several limitations, including labor-intensive preparation, the need for specialized biosafety facilities, and lengthy processing times. Moreover, they provide only qualitative results with limited specificity. While homogeneous serological assays offer a simpler approach to detect Abs in biological samples, their sensitivity is often compromised by high background interference. In this study, we present a time-resolved fluorescence energy transfer (TR-FRET) assay for detecting infectious disease Abs in human sera. Our assay demonstrates high sensitivity in distinguishing between an antigen and its specific antibody, with no detectable upper limit of detection or prozone effect. It is universally applicable to various antigen–antibody complexes including SARS-CoV-2 and influenza, delivers accurate results within 15 minutes, and effectively mitigates background noise from human specimens. The development of this highly accurate immunoassay will enhance serological testing, making it faster, more reliable, and suitable for point-of-care settings.