Abstract
Serological (antibody detection) tests for tuberculosis (TB) are widely used in developing countries. As part of a World Health Organization policy process, we performed an updated systematic review to assess the diagnostic accuracy of commercial serological tests for pulmonary and extrapulmonary TB with a focus on the relevance of these tests in low- and middle-income countries. We used methods recommended by the Cochrane Collaboration and GRADE approach for rating quality of evidence. In a previous review, we searched multiple databases for papers published from 1 January 1990 to 30 May 2006, and in this update, we add additional papers published from that period until 29 June 2010. We prespecified subgroups to address heterogeneity and summarized test performance using bivariate random effects meta-analysis. For pulmonary TB, we included 67 studies (48% from low- and middle-income countries) with 5,147 participants. For all tests, estimates were variable for sensitivity (0% to 100%) and specificity (31% to 100%). For anda-TB IgG, the only test with enough studies for meta-analysis, pooled sensitivity was 76% (95% CI 63%-87%) in smear-positive (seven studies) and 59% (95% CI 10%-96%) in smear-negative (four studies) patients; pooled specificities were 92% (95% CI 74%-98%) and 91% (95% CI 79%-96%), respectively. Compared with ELISA (pooled sensitivity 60% [95% CI 6%-65%]; pooled specificity 98% [95% CI 96%-99%]), immunochromatographic tests yielded lower pooled sensitivity (53%, 95% CI 42%-64%) and comparable pooled specificity (98%, 95% CI 94%-99%). For extrapulmonary TB, we included 25 studies (40% from low- and middle-income countries) with 1,809 participants. For all tests, estimates were variable for sensitivity (0% to 100%) and specificity (59% to 100%). Overall, quality of evidence was graded very low for studies of pulmonary and extrapulmonary TB. Despite expansion of the literature since 2006, commercial serological tests continue to produce inconsistent and imprecise estimates of sensitivity and specificity. Quality of evidence remains very low. These data informed a recently published World Health Organization policy statement against serological tests. Please see later in the article for the Editors' Summary.
Highlights
Despite impressive advances in tuberculosis (TB) control over the last decade [1], missed diagnoses continue to fuel the global epidemic, leading to more severe illness for patients and enabling further transmission of Mycobacterium tuberculosis [2]
Serological tests appear to offer several advantages: (1) the result from a serological test using the enzyme-linked immunosorbent assay (ELISA) format could be available within hours, and the result using an immunochromatographic assay format, within minutes; (2) a serological test, if developed into a point-of-care test, could potentially replace microscopy or extend testing to lower levels of health services; and (3) in children, for whom sputum is difficult to obtain, and in patients suspected of having extrapulmonary TB, a blood test may be more practical
We scored each item as ‘‘yes,’’ ‘‘no,’’ or ‘‘unclear.’’ We considered representative patient spectrum to be persons suspected of having active TB who were consecutively or randomly enrolled
Summary
Despite impressive advances in tuberculosis (TB) control over the last decade [1], missed diagnoses continue to fuel the global epidemic, leading to more severe illness for patients and enabling further transmission of Mycobacterium tuberculosis [2]. Smear microscopy and chest radiography, the primary tools used in resourcelimited countries for identifying TB, often perform poorly, especially in HIV-coinfected patients [3,4,5] Improved techniques, such as liquid culture for M. tuberculosis and nucleic acid amplification tests, are often too expensive and complex for routine use in resourcelimited settings. Mycobacterium tuberculosis, the bacterium that causes tuberculosis, is spread in airborne droplets when people with the disease cough or sneeze It usually infects the lungs (pulmonary tuberculosis) but can infect the lymph nodes, bones, and other tissues (extrapulmonary tuberculosis). Diagnostic tests for the disease include microscopic examination of sputum (mucus brought up from the lungs by coughing) for M. tuberculosis bacilli, chest radiography, mycobacterial culture (in which bacteriologists try to grow M. tuberculosis from sputum or tissue samples), and nucleic acid amplification tests (which detect the bacterium’s genome in patient samples). Tuberculosis can usually be cured by taking several powerful drugs daily or several times a week for at least six months
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
