Bisognin Francesco, Lombardi Giulia, Re Maria Carla, Dal Monte Paola
Microbiology Unit, Department of Experimental, Diagnostic and Specialty Medicine, S. Orsola-Malpighi University Hospital, Bologna, Italy.
Microbiology Unit, Department of Experimental, Diagnostic and Specialty Medicine, S. Orsola-Malpighi University Hospital, Bologna, Italy
J Clin Microbiol. 2020 Sep 22;58(10). doi: 10.1128/JCM.00780-20.
QuantiFERON-TB Gold Plus (QFT-Plus) is the most widely used interferon gamma release assay (IGRA) for the diagnosis of latent tuberculosis infection (LTBI). The aim of this study was to compare QFT-Plus results by enzyme-linked immunosorbent assay (ELISA) on the SkyLab system with those obtained with chemiluminescence immunoassay (CLIA) on the Liaison XL analyzer. Agreement between the two assays was evaluated on 419 QFT-Plus blood samples and was found to be substantial (75.4%); higher agreement was found for positive (95.4%) and negative (80.4%) results, while most discordances were due to ELISA-indeterminate/CLIA-determinate results. According to Italian Clinical Microbiologist Association recommendations, in samples ( = 79) with a borderline result in ELISA (0.20 to 0.70 IU/ml), CLIA median values statistically increased (from 0.29 to 0.59 IU/ml for TB1 and from 0.32 to 0.60 IU/ml for TB2) but remained in the borderline range. Linear regression analysis indicated a substantial correlation between ELISA and CLIA for antigen tubes TB1 (Pearson's = 0.8666) and TB2 (Pearson's = 0.8728), but CLIA produced higher values than ELISA. Receiver operating characteristic (ROC) analysis showed that the optimal cutoff value in CLIA was 0.45 IU/ml for TB1 and 0.46 IU/ml for TB2. In conclusion, automated QFT-Plus with CLIA is comparable to QFT-Plus performed by ELISA. Within the linearity range of the test, CLIA detects higher quantitative values than ELISA, resulting in a higher number of determinate results and the conversion of samples that were close to the cutoff into positive borderline results. A higher cutoff for QFT-CLIA needs to be defined based on clinical diagnostic criteria.
QuantiFERON-TB Gold Plus（QFT-Plus）是用于诊断潜伏性结核感染（LTBI）的最广泛使用的干扰素γ释放试验（IGRA）。本研究的目的是比较在SkyLab系统上通过酶联免疫吸附测定（ELISA）获得的QFT-Plus结果与在Liaison XL分析仪上通过化学发光免疫测定（CLIA）获得的结果。对419份QFT-Plus血液样本评估了两种检测方法之间的一致性，发现一致性很高（75.4%）；阳性（95.4%）和阴性（80.4%）结果的一致性更高，而大多数不一致是由于ELISA不确定/CLIA确定的结果。根据意大利临床微生物学家协会的建议，在ELISA结果处于临界值（0.20至0.70 IU/ml）的样本（n = 79）中，CLIA的中位数统计增加（TB1从0.29至0.59 IU/ml，TB2从0.32至0.60 IU/ml），但仍处于临界范围内。线性回归分析表明，抗原管TB1（Pearson's r = 0.8666）和TB2（Pearson's r = 0.8728）的ELISA和CLIA之间存在显著相关性，但CLIA产生的值高于ELISA。受试者操作特征（ROC）分析表明，CLIA中TB1的最佳临界值为0.45 IU/ml，TB2为0.46 IU/ml。总之，采用CLIA的自动化QFT-Plus与ELISA进行的QFT-Plus相当。在检测的线性范围内，CLIA检测到的定量值高于ELISA，导致确定结果数量更多，并将接近临界值的样本转换为阳性临界结果。需要根据临床诊断标准定义更高的QFT-CLIA临界值。
