Laboratory Diagnosis of Extra-pulmonary Tuberculosis (EPTB) in Resource-constrained Setting: State of the Art, Challenges and the Need.

During the last decade, remarkable progress has been made in the diagnostics of pulmonary tuberculosis; however, diagnostic challenges in extra-pulmonary tuberculosis (EPTB) remain to be addressed. Diagnosis of EPTB is difficult due to the pauci-bacillary nature of disease, the variable clinical presentation, and need for invasive procedures to secure appropriate sample, and lack of laboratory facilities in the resource-limited settings. A more accurate test to diagnose various forms of EPTB, which can easily be incorporated in the routine TB control programme, would contribute significantly towards improving EPTB case-detection and thus reducing the morbidity and mortality. In this overview, we describe the status of current conventional and newer methods available for laboratory diagnosis of EPTB and discuss the challenges in their implementation in the resource-limited settings, and suggestion for better EPTB diagnostic algorithms, which can be incorporated in the routine TB control programmes.