Derrick P Smit1, Tonya M Esterhuizen2, David Meyer1. 1. a Division of Ophthalmology, Faculty of Medicine and Health Sciences, Stellenbosch University , Cape Town , South Africa. 2. b Biostatistics Unit, Centre for Evidence Based Health Care, Faculty of Medicine and Health Sciences , Stellenbosch University , Cape Town , South Africa.
Abstract
PURPOSE: To compare QuantiFERON®-TB Gold and tuberculin skin testing as diagnostic tests for intraocular tuberculosis in HIV positive and negative patients. METHODS: A prospective study evaluating two different tests to help diagnose intraocular tuberculosis. RESULTS: Thirty-five of 106 patients (33.0%) were diagnosed with intraocular tuberculosis including 11 (31.4%) with HIV infection. Patients were 6.95 times more likely to have intraocular tuberculosis if TST alone was positive (p < 0.001) versus 2.19 times more likely if Quantiferon alone was positive (p = 0.04). Tuberculin skin testing showed superior specificity (60.3% vs 33.3%) (p = 0.001) but similar sensitivity (90.3% vs 85.7%), positive (54.9% vs 40.5%) and negative predictive values (92.1% vs 81.5%) compared to Quantiferon. Specificity did not increase significantly if both skin testing and Quantiferon were positive. CONCLUSIONS: In South Africa, with its high HIV burden and limited public health resources, Quantiferon testing should not replace tuberculin skin testing as it provides little additional diagnostic information.
PURPOSE: To compare QuantiFERON®-TB Gold and tuberculin skin testing as diagnostic tests for intraocular tuberculosis in HIV positive and negative patients. METHODS: A prospective study evaluating two different tests to help diagnose intraocular tuberculosis. RESULTS: Thirty-five of 106 patients (33.0%) were diagnosed with intraocular tuberculosis including 11 (31.4%) with HIV infection. Patients were 6.95 times more likely to have intraocular tuberculosis if TST alone was positive (p < 0.001) versus 2.19 times more likely if Quantiferon alone was positive (p = 0.04). Tuberculin skin testing showed superior specificity (60.3% vs 33.3%) (p = 0.001) but similar sensitivity (90.3% vs 85.7%), positive (54.9% vs 40.5%) and negative predictive values (92.1% vs 81.5%) compared to Quantiferon. Specificity did not increase significantly if both skin testing and Quantiferon were positive. CONCLUSIONS: In South Africa, with its high HIV burden and limited public health resources, Quantiferon testing should not replace tuberculin skin testing as it provides little additional diagnostic information.
Entities:
Keywords:
HIV; Quantiferon; South Africa; diagnosis; intraocular tuberculosis; tuberculin skin test