This assay is an indirect test for Mycobacterium tuberculosis infection including disease and is intended for use in conjunction with clinical findings and other diagnostic tests. A positive result indicates the IFN-Gamma response to M. tuberculosis antigens in patient’s sample suggestive of probable exposure to M. tuberculosis. In children less than 5 years of age, Tuberculin skin test (TST) is recommended over IGRA. TB Gold Plus should be performed concurrently or within 3 days of the skin test to avoid the boosting phenomenon. The systematic boosting of the IGRA assay response is seen in TST-positive individuals when it is performed 2 to 4 weeks after TST. It is advisable that the sample for TB Gold Plus should be drawn on the same day of vaccination or 4 to 6 weeks after the administration of a live-virus vaccine. TB Gold Plus is a recommended screening test for those patients being placed on biologic treatment and other immunosuppressive therapy. In patients suffering from LTBI, it is critical to screen for TB infection prior to initiation of immunosuppressive treatment, including biologic agents for autoimmune diseases as introduction of biologics can cause a latent tuberculosis infection (LTBI) to activate due to immunosuppression.