In vitro tests have been developed for the diagnosis of tuberculosis (TB) infection. The objective was to analyse latent TB infection in drug and alcohol abusers through two interferon-γ techniques. One hundred and thirty-nine patients were admitted between February 2006 and May 2007. Mean age was 39.8 years [31% HIV positive]. The enzyme immunoassay (EIA) and enzyme-linked immunospot (ELISPOT) interferon- γ assays were positive in 34% of patients with an agreement of 83% (κ = 0.63). Tuberculin skin test (TST) was positive in 29% of patients and the agreement of TST with EIA and ELISPOT interferon- γ assays was 85% (κ = 0.62) and 83% (κ=0.57), respectively. Almost 50% of patients with history of TB had a positive in vitro test. In conclusion, we observed a high prevalence of latent TB and good agreement between the new in vitro tests that otherwise may continue to be positive long after developing TB disease. © 2009 Cambridge University Press.
- Diagnosis of infection
- Drug abuse