Sensitivity and specificity of a multi-antigen ELISA test for the serological diagnosis of tuberculosis

A new serological assay (DETECT-TB, BioChem ImmunoSystems), using three recombinant proteins and two synthetic peptides for the detection of the anti-Mycobacterium tuberculosis IgG, was evaluated using a panel of serum specimens collected from 100 tuberculosis (TB) patients and 270 controls, in comparison with a homemade ELISA test using purified protein derivative (PPD) as antigen. DETECT-TB presented a higher sensitivity (75%) compared to PPD-ELISA (56%; P < 0.01), while the specificity of each assay was similar (DETECT-TB 97%; PPD-ELISA 100%; P > 0.80). Receiver operating characteristics (ROC) analysis obtained with these data confirmed the higher level of performance of DETECT-TB in comparison with PPD-ELISA. Considering the rapidity, cost-effectiveness and simplicity of this assay, its use may provide useful clinical information aiding in the rapid diagnosis of difficult TB cases.