The Role of QuantiFERON®-TB Gold and Tuberculin Skin Test as Diagnostic Tests for Intraocular Tuberculosis in HIV-Positive and HIV-Negative Patients in South Africa.

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.