Utility of QuantiFERON TB gold test in a south Indian patient population of ocular inflammation

Aim : To study the utility of interferon-g release assays (QuantiFERON TB gold test) in a south Indian patient population of intraocular inflammation. Design : Evaluation of a diagnostic test- a pilot study from January 2007 to October 2008. Materials and Methods : QuantiFERON TB gold test was performed on the following groups of patients following an informed consent. Group A included healthy volunteers without any exposure to tuberculosis (TB) or past history of TB (n=22). Group B included patients with active systemic TB diagnosed by the demonstration of acid-fast bacilli or by the histopathology finding of caseation with granuloma formation from the sputum, lymph node, skin or intestinal biopsies (n=26). Group C included patients with uveitis of known etiologies other than intraocular TB without any history of exposure to active TB (n=21). Group D included patients with a diagnosis of presumed intraocular TB, who responded to antitubercular therapy by decreased or no recurrences following treatment and with a minimum of nine months follow-up following initiation of antitubercular therapy (n=39). Results : The sensitivity and specificity of the QuantiFERON TB gold test to pick up active systemic TB was 58 and 77 respectively. The sensitivity and specificity of the QuantiFERON TB gold test to pickup intraocular TB was 82 and 76 respectively. Conclusions : QuantiFERON TB gold test alone may not be specific for intraocular TB. The significance of this test in a case scenario needs to be interpreted with clinical presentation and other evidences for intraocular TB.