Tuberculosis in Resource- Limited Settings: A Need for Diagnostic Algorithm

• A.O Kehinde

In spite of huge burden of tuberculosis (TB) worldwide, detection of infectious cases continues to be low, thus jeopardizing global TB control efforts especially in resource-limited high burden countries. It is no longer news that vast majority of global TB is diagnosed by a century old method - smear microscopy. Though the method is inexpensive and simple to use, it performs poorly for the diagnosis of TB/HIV co-infections, childhood TB, extra-pulmonary TB and detection of multidrug resistant Mycobacterium tuberculosis (MDR-TB). Although, isolation of the causative pathogen in pure culture is the definitive bacteriological diagnosis of TB, it takes days or weeks to accomplished, thus leading to delayed therapy. Rapid diagnostic tools such as Line probe assay (LPA) and GeneXpert/Rif have revolutionarized TB diagnosis in recent times. However, apart from high cost of equipment and consumables, LPA requires elaborate laboratory space and trained laboratory workers. The major limitation to use of GeneXpert/Rif is the high cost of the equipment and the need for annual calibration. This review aims at highlighting the various methods employed in the diagnosis of active TB and their limitations. It consists of literature search of relevant journals and chapters in books and focuses on microscopy, culture and rapid diagnostic methods in TB. The review has revealed the need to develop an algorithm for use of TB diagnostic tools in resource -limited high burden countries in order to reduce the burden of the disease in the community.

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