QuantiFERON-TB gold cut-off value: implications for the management of tuberculosis-related ocular inflammation

Abstract

Purpose: To evaluate the accuracy of QuantiFERON-TB Gold testing in patients with presumptive tuberculosis-ocular inflammation.

Design: Prospective nonrandomized case series and clinical laboratory investigation.

Methods: Ninety-six consecutive patients presenting with ocular inflammation between January and October 2007 were tested using QuantiFERON-TB Gold. Positive patients received a 6-month anti-tuberculosis treatment. Patient follow-up ranged from 12 months to 24 months. Treatment was considered effective at the end of follow-up, in cases of no or a 2-point decrease of ocular inflammation (SUN criteria) and systemic corticosteroids stopped or tapered to 10 mg/day.

Results: Mean age was 51 ± 17 years. Types of ocular inflammation included scleritis (n = 7), panuveitis (n = 34), and posterior (n = 15), intermediate (n = 14), and anterior uveitis (n = 15). QuantiFERON-TB Gold was positive in 42 cases (44%), negative in 51 cases (53%), and undetermined in 3 cases (3%). Among positive QuantiFERON-TB Gold patients, 25 received a full anti-tuberculosis treatment, which was effective in 15 cases (60%). Associated systemic steroids were given to 6 patients and tapered to 10 mg/day or less in all cases. Median QuantiFERON-TB Gold value was significantly higher in the group with a successful therapeutic response (7.67 IU/mL [0.46 to 33.37]) compared to the group with treatment failure (1.22 IU/mL [0.61 to 4.4]), P = .026.

Conclusion: Results of anti-tuberculosis treatment were encouraging in QuantiFERON-TB Gold-positive ocular inflammation, especially with values over 2 IU/mL in our study, suggesting that a higher cut-off value than that given by the manufacturer should be considered to better identify ocular inflammation that can benefit from full anti-tuberculosis treatment.