A Case-Control Study on The Diagnostic Potential of Multi-Antigen Serological Tests for Tuberculosis

Abstract

ackground: Eradicating tuberculosis (TB) in European countries with high incidence, such as Portugal, rely to a great extent on the ability to perform early accurate diagnosis. For the first time, the diagnostic value of two serologic tests, TB STAT-PAK II and MAPIA, was evaluated for rapid tuberculosis detection in a Portuguese cohort. Materials and Methods: A multicentre case-control study was performed on individuals who had been followed up for TB. Serum was collected from a total of 157 patients divided in: 1) control group with 32 healthy individuals 2) control group with 30 patients with pulmonary diseases other than TB; 3) patients with active TB on anti-TB medication for less than 2 weeks (43 patients), for 1 to 2 months (32 patients) or for more than 6 months (28 patients); 4) 25 patients with active TB co-infected with human immunodeficiency virus (HIV); 5) 29 recently exposed individuals with probable latent TB infection. Sera were tested for the presence of specific mycobacteria antibodies using the TB STAT-PAK II and MAPIA tests and compared with sputum smear microscopy information. Findings: Both of the serological methods showed high specificity. However the two methods had sub-optimal sensitivity, especially in HIV-co-infected patients. Combination of the antibody assays with sputum smear microscopy increased the overall sensitivity of rapid diagnosis. Conclusions: The use of point-of-care serodiagnostic tests may improve early detection of active tuberculosis and contribute for better control programs.