I:\Interwov \NRPortbI\DCCVXT\ 9227388 _.doc-27/08/2019 This disclosure relates generally to the field of immunological-based diagnostic assays including an assay to measure cell-mediated immunoresponsiveness. The present disclosure teaches diagnosis of a subject's exposure to an antigen based on cell-mediated immunoresponsiveness with enhanced sensitivity. The assay contemplated herein is capable of integration into standard pathology architecture to provide a diagnostic reporting system and to facilitate point of care clinical management.