title: A systematic review of rapid drug susceptibility tests for multidrug-resistant tuberculosis using rifampin resistance as a surrogate.
abstract: BACKGROUND
  The emergence of multidrug-resistant tuberculosis (MDR-TB) has prompted the development of rapid drug susceptibility assays with a focus on rifampin in recent years. Systematic reviews with evaluation of predictive values for different assays are scarce.
  
  
  METHODS
  MEDLINE was searched on 6 September 2008 for English articles that contain concurrent original data for generating summary measures of sensitivity, specificity and likelihood ratios of rapid rifampin susceptibility assays.
  
  
  CONCLUSIONS
  Significant heterogeneity was found in likelihood ratios across studies of all assays except nitrate reductase assay and colorimetric assays. Although rapid assays are fairly reliable for ruling out MDR-TB, careful consideration of clinical risk factors is required before using these assays to rule in MDR-TB under different epidemiological settings.
authors.affiliation: Senior Medical and Health Officer Tuberculosis and Chest Service, Wanchai Chest Clinic, Department of Health, 1st Floor, Wanchai Polyclinic, 99, Kennedy Road, Wanchai, Hong Kong, China +852 25911147 ; +852 28346627 ; kc_chang@dh.gov.hk.
authors.forename: Kwok-Chiu
authors.initials: KC
authors.lastname: Chang
authors.forename: Wing-Wai
authors.initials: WW
authors.lastname: Yew
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhang