Studies conducted by Mori and colleagues in Japan have shown QuantiFERON ¨ -TB Gold to have a specificity of at least 98% in BCG vaccinated individuals who had no identified risk factors for TB exposure.19
The epidemiologically estimated rate of latent tuberculosis infection (LTBI) in the population tested was 2%, in accordance with the 98% specificity seen.
Specificity of 99% was seen in a study of 99 low-risk individuals in Australia, and >800 low risk individuals in the United States.
The QuantiFERON ¨ -TB Gold test has been demonstrated to be highly reproducible before and after skin testing (99.3%) and tuberculin skin testing performed within 4 weeks has no effect on the QuantiFERON ¨ -TB Gold assay.
QuantiFERON ¨ -TB Gold In-Tube was also used in Australian and US specificity studies and gave the same specificity outcomes.
QuantiFERON ¨ -TB Gold In-Tube provides higher signal to noise in infected individuals than standard QuantiFERON ¨ -TB Gold and may confer higher sensitivity.
