Comparison of QuantiFERON TB-G-test to TST for detecting latent tuberculosis infection in a high-incidence area containing BCG-vaccinated population.
OBJECTIVE
Until recently, the only tool for detection of latent tuberculosis infection (LTBI) was the tuberculin skin test (TST). QuantiFERON-TB Gold In-Tube test (QFT) is a promising in vitro diagnostic test for LTBI that has potential advantages over the TST. In this study we aimed to compare QFT with TST for diagnosis of LTBI.


METHODS
A total of 186 BCG-vaccinated subjects enrolled in study. They underwent TST and QFT assay. They divided in two groups. Group 1 includes individuals who were at low risk for exposure to M. tuberculosis (LRG) and Group 2 includes individuals who were likely to have been exposed to M. tuberculosis infections (HRG).


RESULTS
Overall agreement between QFT and TST was 89.3% (kappa = 0.052). In LRG, agreement between the two tests was 52.6% (95% confidence interval, 44-60%) with kappa-values of 0.019. In HRG agreement between the two tests was 63.2% (95% confidence interval, 42-84%) with kappa-values of 0.28.


CONCLUSIONS
In conclusion, the QFT assay showed acceptable results for determining latent M. tuberculosis infection in vaccinated population. The decision to select QFT over TST will depend on the population, purpose of testing and resource availability.
Kariminia
Amina
A
Immunology Department Pasteur Institute of Iran, Tehran, Iran.
Sharifnia
Zarin
Z
Aghakhani
Arezoo
A
Banifazl
Mohammad
M
Eslamifar
Ali
A
Hazrati
Mahboob
M
Ramezani
Amitis
A
D000328:Adult; D001500:BCG Vaccine / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D007124:Immunoenzyme Techniques; D007371:Interferon-gamma / Q000097:blood*; D007492:Iran / Q000453:epidemiology; D008297:Male; D009169:Mycobacterium tuberculosis / Q000302:isolation & purification*; D015203:Reproducibility of Results; D012882:Skin Tests; D014376:Tuberculosis / Q000175:diagnosis* / Q000453:epidemiology; D055815:Young Adult
D001500:BCG Vaccine; D007371:Interferon-gamma