Usefulness of the QuantiFERON test for the diagnosis of tubercular uveitis and the predictions of response to antituberculosis treatment.

AIMS Few studies have evaluated the contribution of QuantiFERON test for the diagnosis of tubercular uveitis in non-endemic countries for tuberculosis (TB). The objective of the present study was to evaluate the value of the QuantiFERON test in a large cohort of patients with uveitis for both the diagnosis of tubercular uveitis and antituberculosis treatment (ATT) response prediction. METHODS A single-centre retrospective study including consecutive adult patients with uveitis who were prescribed a QuantiFERON test between January 2003 and December 2019 was performed. Adjusted ORs (aORs) were calculated between patients with uveitis responding and not responding to ATT according to the Collaborative Ocular Tuberculosis Study (COTS) group diagnostic criteria. Sensitivity (SE), specificity (Sp), and positive and negative predictive values of the QuantiFERON test were calculated. RESULTS A total of 1075 patients were included in the study; 178 (16.5%) were found positive using the QuantiFERON test. Among the 178 positive patients, 62 (35%) had a diagnosis of tubercular uveitis according to the updated COTS classification; all received ATT for 6 months; and 44/62 (71%) responded to ATT. A QuantiFERON test value of >2 IU/mL was associated with a greater chance of responding to ATT (aOR=36.7, 95% CI 7.2 to 185.9, p<0.001). The optimal threshold to maximise both Sp and SE for diagnosis of TB uveitis was 4 IU/mL. CONCLUSION One-sixth of the patients diagnosed with uveitis had a positive QuantiFERON test. The QuantiFERON threshold with the optimal SE and Sp for the diagnosis of tubercular uveitis was 4 IU/mL. TRIAL REGISTRATION NUMBER NCT03863782.