title: Performance of a lateral flow immunochromatography test for the rapid diagnosis of active tuberculosis in a large multicentre study in areas with different clinical settings and tuberculosis exposure levels.
abstract: BACKGROUND
  Tuberculosis (TB) continues to cause an outsized burden of morbidity and mortality worldwide, still missing efficient and largely accessible diagnostic tools determining an appropriate control of the disease. Serological tests have the potentially to impact TB diagnosis, in particular in extreme clinical settings.
  
  
  METHODS
  The diagnostic performances of the TB-XT HEMA EXPRESS (HEMA-EXPRESS) immunochromatographic rapid test for active TB diagnosis, based on use of multipleMycobacterium tuberculosis(MTB) specific antigens, have been evaluated in a large study multicentre TB case-finding study, in populations with different exposure level to TB. A total of 1,386 subjects were enrolled in the six participating centres in Peru: 290 active-TB and 1,096 unaffected subjects.
  
  
  RESULTS
  The TB prevalence (overall 20.5%) varied between 4.0% and 41.1% in the different study groups. Overall, the HEMA-EXPRESS test had 30.6% sensitivity (range 3.9-77.9%) and 84.6% specificity (range 51.6-97.3%). A significant inverse correlation between test accuracy (overall 73.5%, range 40.4-96.4%) and TB prevalence in the various study populations was observed (Pearson's r=-0.7985; P=0.05).
  
  
  CONCLUSIONS
  HEMA-EXPRESS, is rapid and relatively inexpensive test suitable for routine use in TB diagnosis. In low TB prevalence conditions, test performance appears in line with WHO Target Product Profile for TB diagnostics. Performances appear suboptimal in high TB prevalence settings. Appropriate set-up in operative clinical settings has to be considered for novel serological tests for TB diagnosis, particularly for formats suitable for point-of-care use.
authors.affiliation: Department of Infectious Diseases, University National San Antonio Abad Cusco, Cusco, Peru.
authors.forename: Selene
authors.initials: S
authors.lastname: Manga
authors.affiliation: Peruvian Ministry of Health, Primary Health Care Facility of Surquillo, Lima, Peru.
authors.forename: Rocio
authors.initials: R
authors.lastname: Perales
authors.affiliation: Peruvian Ministry of Health, Primary Health Care Facility of Surquillo, Lima, Peru.
authors.forename: Maria
authors.initials: M
authors.lastname: Reaño
authors.affiliation: WHO Collaborating Centre for TB and Lung Diseases, Maugeri Institute, IRCCS, Tradate, Italy;
authors.forename: Lia
authors.initials: L
authors.lastname: D'Ambrosio
authors.affiliation: WHO Collaborating Centre for TB and Lung Diseases, Maugeri Institute, IRCCS, Tradate, Italy.
authors.forename: Giovanni Battista
authors.initials: GB
authors.lastname: Migliori
authors.forename: Massimo
authors.initials: M
authors.lastname: Amicosante
keywords: Latin America; Tuberculosis (TB); diagnosis; later flow immunochromatography; multicentre study; rapid test; serology