Patent ID: 8722061

Claim:
A method of diagnosis of tuberculosis in a human subject, the method comprising: exposing a serum sample of the human subject to at least three different M. tuberculosis protein antigens separately immobilized on different locations on a surface of an assay, wherein the at least three different M. tuberculosis protein antigens include at least one antigen of a first type selected from the group consisting of 16 kDa antigen (product of gene rv 2031c) and ESAT-6 antigen (product of gene rv 3875), at least one antigen of a second type selected from the group consisting of Rv2626c antigen, AlaDH antigen (product of gene rv 2780) and 38 kDa antigen (product of gene rv 0934), and at least one antigen of a third type selected from the group consisting of 16 kDa antigen (product of gene rv 2031c), ESAT-6 antigen (product of gene rv 3875), Rv2626c antigen, AlaDH antigen (product of gene rv 2780) and 38 kDa antigen (product of gene rv 0934); detecting serum antibodies to the antigens on the assay; measuring the signal strength of the response of the serum antibodies to the antigens on the assay to determine the level of antibodies present in the serum; comparing (a) the signal strength of the response of the serum antibodies to the 16 kDa antigen, ESAT-6 antigen, Rv2626c antigen, or AlaDH antigen with a median of responses to the 16 kDa antigen, ESAT-6 antigen, Rv2626c antigen, or AlaDH antigen, said median being obtained from a group of characterized serum or a study human population, or (b) the signal strength for the response of the serum antibodies to the 38 kDa antigen with a first tertile of responses to the 38 kDa antigen, said first tertile being obtained from the group of characterized serum or the study human population; categorizing the level of antibodies to each selected antigen (i) as a high level if the signal strength is higher than the median or (ii) as a low level if the signal strength is lower than the median or the first tertile; and determining whether the signal strength is indicative of active tuberculosis, inactive tuberculosis or chest x-ray normal, wherein high levels of antibodies to 16 kDa antigen (product of gene rv 2031c) and ESAT-6 antigen (product of gene rv 3875) and low levels of antibodies to Rv2626c antigen, AlaDh antigen (product of gene rv 2780) and 38 kDa antigen (product of gene rv 0934) are indicative of a likelihood of inactive tuberculosis over active tuberculosis, and wherein high levels of antibodies to 16 KDa antigen (product of gene rv 2031c) and ESAT-6 antigen (product of gene rv 3875) are indicative of the likelihood of inactive tuberculosis over chest x-ray normal.