Tuberculosis and its Diagnosis: Past, Present and Future

Tuberculosis is an endemic disease in the developing countries worldwide. Early and definitive diagnosis of Active Pulmonary Tuberculosis (TB) is important both at individual and population level for reducing mortality as well as transmission of the disease. Currently available diagnostics can be broadly categorized into microscopy, culture based and molecular method-based approaches. Among the advanced molecular methods, the Nucleic Acid Amplification Test (NAA), Line Probe Assay and Cartridge Based Nucleic Acid Amplification Test (CB NAAT) are mentionable. However, all these diagnostic methods either have compromised sensitivity or require expensive instrumentations that ultimately limit their efficacy as established diagnostic method. Currently used rapid and affordable diagnostic test for TB is sputum microscopy that detects Mycobacterium tuberculosis (Mtb) in clinical sample. This test has sub-optimal sensitivity as it depends firstly on the abundance of Mtb in the sample and secondly on operator’s accuracy. On the other hand, culture-based diagnostic tests are time-consuming and dependent on expertise and infrastructure. Likewise, molecular tests are also dependent on expensive instrumentation and technical sophistication. Hence, rapid, sensitive and affordable diagnostic method for the detection of Active Pulmonary tuberculosis at an early phase is still a primary requisite.