Controversies and Pitfalls in the Diagnosis of Extrapulmonary Tuberculosis with a Focus on Genital Tuberculosis

Abstract

Extrapulmonary tuberculosis (EPTB) is a complex disease; diagnosis is often difficult due to the paucibacillary status and the invasive procedures required to obtain an adequate sample. Culture testing remains the gold standard for diagnosis, but low bacterial count in EPTB may lead to a negative culture; therefore, a combination of tests is often required for confirmation of diagnosis. Microbiological tests are combined with clinical signs and symptoms, in addition to imaging techniques to improve diagnostic accuracy. Molecular tests have improved time-to-detection for disease and drug sensitivity testing; however, they cannot replace culture testing at present. Though specificity of molecular testing is high, sensitivity varies in samples from different sites, being low for TB meningitis. For genital TB, a combination of tests must be used for timely diagnosis, as disease progression leads to irreversible damage of the reproductive organs. Newer techniques, like whole genome sequencing and next-generation sequencing, are being introduced to improve diagnosis and detect drug resistance. Currently, no single diagnostic test can be considered a ‘point of care’ test. Early and accurate diagnosis is urgently needed to prevent the associated morbidity and mortality.