Abstract: Objective To discuss the significance of the detection of interferon-γ in the diagnosis of active joint tuberculosis. Methods 5 kinds of specific proteins of mycobacterium tuberculosis were used as stimulating protein, the chemiluminescence enzyme immunoassay was used to test the content of interferon-γ. The interferon-γ of 35 cases of patients with active joint tuberculosis and 35 cases of healthy people were detected. The difference of the sensitivity, specificity, positive predictive value, negative predictive value, positive likelihood ratio and negative likelihood ratio of 5 kinds of proteins to the diagnostic of active joint tuberculosis were compared. Results CFP10/ESAT6 fusion protein, Rv2041c protein, Rv0057/1352 fusion proteins, Rv1419 protein and Rv1656 protein were used as stimulating protein, the sensitivities of active joint tuberculosis by the whole blood interferon-γ assay were 77.1%, 68.6%, 71.4%, 74.3 % and 65.7%. The specificities were 65.7%, 54.3%, 57.1%, 60.0% and 62.9%. The positive predictive values were 62.9%, 60%, 62.5%, 65% and 63.9%. The negative predictive values were 74.2%, 63.3%, 66.7%, 70% and 64.7%. The positive likelihood ratios were 2.25, 1.5, 1.67, 1.86 and 1.77. The negative likelihood ratios were 0.348, 0.579, 0.5, 0.429 and 0.545. Conclusion The detection of interferon-γ has certain significance to joint tuberculosis.
But it is not as an index of diagnosing joint tuberculosis.

Key words: joint tuberculosis, interferon-gamma, diagnosis, mycobacterium tuberculosis, specific proteins