Assessment of the validity of rapid diagnostic test kits available in the Nigerian market for Mycobacterium tuberculosis

Abstract

Tuberculosis (TB) is an infectious disease caused by various strains of mycobacteria, usually Mycobacterium tuberculosis. Early diagnosis is important in TB disease control. The use of rapid diagnostic test (RDT) kits drastically reduces the time required for reaching clinical diagnosis and this has been successful in diagnosis of HIV, syphilis and more recently malaria to mention a few. What is the case for RDTs for diagnosis of tuberculosis? Thus, the aim of this study is to evaluate and compare the performances of results produced by different rapid diagnostic test strips available in the Nigerian market for TB. A total of one hundred and eighty-four (184) subjects aged between 12-68 years were recruited for the study. These were referred from the chest clinic with a high index of suspicion of TB. Sputum samples were collected for AFB detection using the Ziehl-Neelsen and Auramine-phenol staining techniques. Blood samples were collected for serology tests using five (5) different rapid diagnostic test kits from different manufacturers, HIV status determination and evaluation of the haematological parameters we carried out. As a result, there were significant differences in the results obtained between AFB tests and serological methods with P<0.01 in all cases. The sensitivity and specificity respectively of the five different kits were 28.6% and 32.0% (Nova), 19.5% and 29.2% (Fistech), 9.1% and 27.1% (Diaspot), 12.4% and 27.7% (Abcon) and 12.4% and 27.7% (Global).finally, findings from this study show that these rapid serological tests are poor in diagnosing tuberculosis and cannot be recommended for use in this environment.
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Keywords: Tuberculosis, rapid diagnostic tests, acid fast bacilli