Evaluation of the effect of treatment of latent tuberculosis infection on QuantiFERON-TB gold assay results.

To evaluate the utility of the QuantiFERON-TB Gold assay for monitoring latent tuberculosis treatment efficacy, the assay was performed serially for healthcare workers receiving isoniazid therapy. After 9 months of isoniazid therapy, all of these healthcare workers remained QuantiFERON-TB Gold positive, and cellular proliferation assays revealed persistently strong purified protein derivative responses. These results do not support the use of the QuantiFERON-TB Gold assay to monitor therapy.