ارزيابي تست گاما اينترفرون خون در تشخيص عفونت نهفته توبركولوزيس به عنوان جايگزيني بالقوه براي تست پوستي مانتو

Blood Gamma Interferon Assay for Detection of Latent Tuberculosis Infection: Potential to Replace the Mantoux Skin Test

Background and Objective: Although the PPD is useful in clinical practice for detection of latent tuberculosis infection (LTBI), it has several limitations .QuantiFERON-TB Gold In-Tube test (QFT) is expected to be more specific for M. tuberculosis diagnosis than PPD. In this study we compared QFT with PPD for diagnosis of LTBI. Materials and methods: 186 BCG-vaccinated subjects enrolled in study. They divided in two groups. Group 1 includes individuals who were at low risk for exposure to M. tuberculosis (LRG) and Group 2 includes individuals who were likely to have been exposed to M. tuberculosis infections (HRG). They underwent PPD and QFT assay. Results: Overall agreement between QFT and PPD was 89.3% (kappa = 0.052). In LRG, agreement between QFT and PPD was 52.6% (kappa = 0.019) and in HRG was 63.2% (kappa = 0.28). The sensitivity and specificity of QFT compared to PPD in LRG were 8% and 93.8% and in HRG were 30% and 100% respectively. Conclusion: Our data suggested that QFT appears to be more specific method for diagnosis of LTBI, especially in HRG.