title: False positive seroreactivity to brucellosis in tuberculosis patients: a prevalence study.
abstract: BACKGROUND
  The rising worldwide incidence of tuberculosis (TB) increases the demand for knowledge about its potential seroreactivity with other microbial agents. A few reports and the authors' experiences indicate that tuberculosis may result in a false-positive brucellosis serology. This may cause a diagnostic challenge because of the close clinical resemblance of these two infections.
  
  
  OBJECTIVE
  The aim of the present prevalence study was to elucidate brucellosis seroreactivity in patients with active TB.
  
  
  METHODS
  Ninety-eight patients with newly diagnosed and active TB were studied using an enzyme-linked immunosorbent assay (ELISA) and Wright's and Coombs-Wright's tests. Seventy-five healthy individuals were used as controls. The patients showed signs of recovery after starting a standard anti-TB regimen and had no clinical evidence of brucellosis at a subsequent 6-month follow-up. The data were analyzed statistically by Fisher's exact test using SPSS 11.0.
  
  
  RESULTS
  We found that 9.2% of TB patients versus 1.3% of healthy controls had positive results on the anti-Brucella IgG ELISA (P = 0.04). Five TB patients were found to have agglutination on Wright's tests, while none of the controls showed agglutination.
  
  
  CONCLUSIONS
  Active TB patients may have some seroreactivity with Brucella antigens, and Brucella IgG ELISA may give a false positive in these patients. Clinicians should consider false positive brucellosis seroreactivity in patients with active TB.
authors.affiliation: Department of Infectious Disease, Tabriz University of Medical Sciences, Tabriz, Iran;
authors.forename: Mojtaba
authors.initials: M
authors.lastname: Varshochi
authors.forename: Jafar
authors.initials: J
authors.lastname: Majidi
authors.forename: Marjan
authors.initials: M
authors.lastname: Amini
authors.forename: Kamyar
authors.initials: K
authors.lastname: Ghabili
authors.forename: Mohammadali M
authors.initials: MM
authors.lastname: Shoja