Point-of-care ultrasound for diagnosing extrapulmonary TB

BACKGROUND Despite the high morbidity and mortality globally, standard microbiologic diagnosis for TB requires laboratory infrastructure inaccessible in many resource-limited areas and may be insufficient for identifying extrapulmonary disease. Point-of-care (POC) ultrasound facilitates visualization of extrapulmonary manifestations, permitting laboratory-independent diagnosis, but its diagnostic utility remains unclear. METHODS We conducted a systematic review of five online databases for studies reporting ultrasound findings among cases with and without extrapulmonary TB (EPTB). A minimum of two authors independently screened and reviewed each article, and extracted data elements of interest. We conducted a series of univariate meta-analyses using a random-effects model to calculate the pooled effect estimate and 95% confidence interval (CI) for each outcome: sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). RESULTS Of 279 articles identified, 6 were included. There were 699 cases of EPTB among 1,633 participants. The pooled sensitivity estimate was 0.72 (95% CI 0.57-0.88). The pooled specificity estimate was 0.77 (95% CI 0.63-0.90). The pooled PPV and NPV estimates were respectively 0.67 (95% CI 0.47-0.87) and 0.85 (95% CI 0.77-0.93). CONCLUSION POC ultrasound showed modest test characteristics for diagnosing EPTB, which may constitute an improvement over some currently available diagnostics. .