Widespread use of serological tests for tuberculosis: data from 22 high-burden countries

To the Editors: There is great excitement over the introduction of new tuberculosis (TB) diagnostics [1]. Since 2007, several TB diagnostics and approaches have been endorsed by the World Health Organization (WHO) [2],with Xpert MTB/RIF (Cepheid, Sunnyvale, CA, USA) being the most recent [3]. Amidst this excitement, there is growing concern surrounding the use of inappropriate and suboptimal TB diagnostics [4, 5]. Currently available commercial serological (antibody detection) tests for TB are inaccurate and highly inconsistent [6–8]. The International Standards for TB Care explicitly discourage their use [9]. Even so, serological tests are known to be widely used in countries such as India [2, 4, 5]. In addition to posing an economic burden on patients and healthcare systems, use of serological tests also entails potential harm to patients ( e.g. unnecessary TB therapy because of false-positive results, or morbidity and mortality because of false-negative serology results). After reviewing the evidence, including the findings of an updated meta-analysis [10], the WHO recently announced its first negative policy in TB, against the use of current TB serological tests [5 …