Epidemiology and Infection

Original Papers

Bacteria

Prospective evaluation of latent tuberculosis with interferon-γ release assays in drug and alcohol abusers

I. RIVASa1, I. LATORREa2, A. SANVISENSa1, J. DOMÍNGUEZa2, J. TORa1, C. PRATa2, C. REY-JOLYa1 and R. MUGAa1 c1

a1 Department of Internal Medicine, Hospital Universitari Germans Trias i Pujol, Badalona, Spain

a2 Department of Microbiology, Hospital Universitari Germans Trias i Pujol, Badalona, Spain

SUMMARY

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.

(Accepted January 16 2009)

(Online publication February 26 2009)

Correspondence:

c1 Author for correspondence: R. Muga, M.D., Ph.D., Department of Internal Medicine, Hospital Universitari Germans Trias i Pujol, Universitat Autònoma de Barcelona, Carretera Canyet s/n, 08916 Badalona, Barcelona. (Email: rmuga.germanstrias@gencat.cat)

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