QuantiFERON® -TB Gold test in the identification of latent tuberculosis infection in immigrants

• Published in: The Journal of infection Vol. 55; no. 2; pp. 164 - 168
• Main Authors: Carvalho, Anna C.C, Pezzoli, Maria Chiara, El-Hamad, Issa, Arce, Patricia, Bigoni, Sara, Scarcella, Carmelo, Indelicato, Anna Maria, Scolari, Carla, Carosi, Giampiero, Matteelli, Alberto
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.08.2007; Elsevier
• Subjects: Adult; Bacterial diseases; Biological and medical sciences; CFP 10; Emigration and Immigration - statistics & numerical data; ESAT-6; Female; Human bacterial diseases; Humans; Immigrants; Infectious Disease; Infectious diseases; Italy - epidemiology; Latent tuberculosis infection; Logistic Models; Male; Medical sciences; Middle Aged; Mycobacterium tuberculosis; QuantiFERON ®-TB Gold; Reagent Kits, Diagnostic; Skin Tests; Tuberculosis - diagnosis; Tuberculosis - epidemiology; Tuberculosis and atypical mycobacterial infections; Italy; CFP 10; QuantiFERON ®-TB Gold; ESAT-6; Latent tuberculosis infection; Immigrants; Infection; Latent tuberculosis; Identification; Immigrant
• ISSN: 0163-4453; 1532-2742
• DOI: 10.1016/j.jinf.2007.02.004

Summary Background The identification and treatment of latent tuberculosis infection (LTBI) among immigrants are an effective strategy for TB control in developed countries. A new test for LTBI identification that uses more specific antigens of Mycobacterium tuberculosis is now commercially available under the brand name of QuantiFERON® -TB Gold test. Objective To compare QuantiFERON® -TB Gold test to tuberculin skin testing (TST) for the detection of LTBI among immigrants from high endemic TB areas. Patients and methods Undocumented immigrants attending a district medical center were enrolled if they originated from high endemic TB areas, the time of arrival in Italy was ≤5 years, had neither active TB disease nor known immunodeficiency status. The TST was applied according to standards and QuantiFERON® -TB Gold test was performed following the manufacturer's instructions. Results Hundred subjects were included in the comparative analysis. TST was positive in 44% of subjects; 15% had a positive QuantiFERON® -TB Gold test result. The total agreement between TST and QuantiFERON® -TB Gold test was 71%, for a κ statistics of 0.37; agreement was 100% for TST negative results, but only 34% for TST positive ones. In the multivariate logistic regression analysis, previous BCG vaccination was independently associated with a lower chance of disagreement between the tests. Conclusion The prevalence of LTBI among immigrants was lower when determined by QuantiFERON® -TB Gold; this may be a consequence of more specific MTB antigens used. Our results suggest that QuantiFERON® -TB Gold may be used as confirmatory test for TST positive immigrants candidate to preventive therapy.