Application value of interferon gamma release assay combined with tuberculin skin test in diagnosis of intraocular tuberculosis and latent tuberculosis infection

Objective To explore the application value of interferon gamma release assay (IGRA) combined with tuberculin skin test (TST) in diagnosis of intraocular tuberculosis and latent tuberculosis infection. Methods One hundred and ten patients with pulmonary tuberculosis (observation group) and 80 healthy persons (control group) in Hebei Chest Hospital from January 2016 to December 2018 were selected. Among the 110 patients with pulmonary tuberculosis, intraocular tuberculosis was in 35 cases, and latent tuberculosis infection was in 75 cases. All the patients were examined by ocular secretions IGRA and TST. Results The positive rates of IGRA and TST in observation group were significantly higher than those in control group: 88.18% (97/110) vs. 11.25% (9/80) and 83.64% (92/110) vs. 41.25% (33/80), and there were statistical differences (χ2 = 113.138 and 36.971, P 0.05. The consistency rate of IGRA and TST was 89.90% (Kappa = 0.867, P>0.05). The sensitivity of IGRA combined with TST was significantly higher than the single detection of IGRA and TST (97.83% vs. 88.18% and 83.64%), while the specificity of IGRA combined with TST was significantly lower than the single detection of IGRA and TST (61.11% vs. 92.31% and 83.33%), and there were statistical differences (P<0.05). The receiver operating characteristic curve analysis result showed that the area under curve of IGRA in diagnosis of intraocular tuberculosis and latent tuberculosis infection was 0.781, area under curve of TST was 0.604, and area under curve of IGRA combined with TST was 0.679. Conclusions IGRA has high value in the diagnosis of intraocular tuberculosis and latent tuberculosis infection, and can be used as a diagnostic means of intraocular tuberculosis. Key words: Tuberculosis, ocular; Tuberculin test; Latent tuberculosis; Interferon gamma release assay