Initial results of QuantiFERON-TB Gold testing in patients with uveitis

Purpose To describe the use of the second-generation QuantiFERON-TB Gold (QFT-G) test in a series of patients in an ophthalmic practice. Methods The charts of all patients who had QFT-G tests ordered by Mayo Clinic ophthalmologists in the past 3 years were reviewed. Results A total of 27 QFT-G tests were ordered. Thirteen (48%) tests were negative, six (22%) were indeterminate, two (7%) tests were re-ordered after a lab accident or an improper cancellation, four (15%) were positive and represented infection, and two (7%) were positive but negative when re-tested. Of the four truly positive cases, three were treated for tuberculosis (TB): one had tuberculous iritis, one had retinal vasculitis and haemorrhage, and one had asymptomatic TB but was on immunosuppressive therapy. The fourth patient had previously been treated for latent infection. Conclusions In a series of selected patients with uveitis, the QFT-G test was able to detect TB infection in 15% of the patients, though it does not differentiate between active and latent TB infection. QFT-G should be considered in place of purified protein derivative testing in those with uveitis that have had prior BCG vaccination and in immunocompromised patients. Patients with a positive QFT-G, but who have little risk for TB infection and a negative systemic work-up, should be re-tested.