A multiplexed and miniaturized serological tuberculosis assay identifies antigens that discriminate maximally between TB and non-TB sera.

We have developed a multiplexed and miniaturized TB serological assay with the aim of identifying (combinations of) antigens that maximally discriminate between TB and non-TB patients. It features a microarray accommodating 54 TB antigens, less than 1 microl serum consumption and an indirect immunofluorescence detection protocol. With a panel of 20 TB and 80 non-TB sera we ranked combinations of TB antigens with respect to sensitivity and specificity of TB detection by means of logistic step-forward regression analysis. The highest-ranking TB antigen combination had an area-under-the-curve of the receiver-operator-characteristics (ROC) of 0.95. We also identified an antigen that on its own provided good specificity and sensitivity of TB detection (Ara6-BSA; area-under-the-ROC curve: 0.90). These area-under-the-ROC curve values are exceptionally high for a serological TB assay. We conclude that TB antigen microarrays permit rapid identification of TB antigens that, either alone or in combination, discriminate maximally between TB and non-TB patients and that such identification provides an excellent starting point for developing point-of-care diagnostic assays.