Tuberculosis Diagnostics, a journey from the past Experiences to the Future Directions, Review

Abstract

Purpose: Tuberculosis caused by Mycobacterium tuberculosis is believed to have been acquired from animals especially cattle. Not one country across the globe is spared of the disease. The infection gets established through respiratory system where they are either latent or active. Depending upon the immune status or coexisting infection or other health disorders the infection may be either contained within the lungs or spread to other parts of the body. Hence rapid and accurate diagnosis is needed to initiate appropriate treatment. Sputum studies are being followed for diagnosis of tuberculosis but has few disadvantages. Xpert MTB/RIF, an automated, molecular test has been in vogue now. Biomarkers such as complete blood count, inflammatory and oxidative stress markers are being measured. Recently epigenetic markers like microRNA are being analyzed to differentiate the various presentations of tuberculosis. This review has been undertaken to understand the various diagnostic strategies being followed from the old times to the newer novel techniques. Methods: The narrative review was undertaken by searching the original and review articles in the past 20 years. The articles were obtained by searching through various search engines. Since this was a review article ethics committee approval was not required. Results: The traditional methods have inherent limitations of high expertise, prolonged procedure, not cost effective and require good infrastructure. Newer methods are found to be sensitive, specific, reproducible and cost effective. But require validation to be implemented into routine use. Conclusions: Validating the new markers such as epigenetic markers – microRNAs should pave way for diagnosis and management of pulmonary TB, extrapulmonary TB, TB in HIV infected individuals, pregnant women and children. This could serve as a finger-print sort of diagnosis once validated on large scale community-based studies.