For indirect diagnosis of tuberculosis, two commercial IGRA (Interferon Gamma Release Assay) assays are available - primal QuantiFERON-TB Gold test, new version QuantiFERON-TB Gold Plus test (four tube, differentiation in activity CD4+ a CD8+) and T-SPOT.TB test. Both methods are based on the same principle, but their workflows are different.
In this article, both assays are compared on the collection of 284 patients. Inter-rate agreement measure showed 81.3% consistency and Cohens kappa index was calculated as 0.72.
In case of discrepancy between IGRA and other methods (clinical aspects, X-ray diagnostic, etc.), results should be confirmed by second IGRA assay for correct interpretation.