Evaluation of the Xpert MTB/RIF Assay at a Tertiary Care Referral Hospital in a Setting Where Tuberculosis and HIV Infection Are Highly Endemic

Diagnosis of tuberculosis in most countries where tuberculosis has a high endemicity relies heavily on smear microscopy, a century-old technology. Although it is simple and inexpensive, the specificity and sensitivity is poor, particularly in human immunodeficiency virus (HIV)–positive patients, as well as in children. Furthermore, it cannot differentiate between disease caused by drug-sensitive Mycobacterium tuberculosis (MTB) and disease caused by drug-resistant M. tuberculosis [1]. In sub-Saharan Africa, an average of only 56% of new cases of pulmonary tuberculosis were smear positive in 2010, with Zimbabwe, Swaziland, and Zambia having the lowest sputum smear–positive case detection rates, at 32%, 37%, and 38%, respectively [2], indicating that