Cesur Salih, Hoca Nevin Taci, Tarhan Gülnur, Cimen Filiz, Ceyhan Ismail, Annakkaya Ali Nihat, Aslan Turan, Birengel Serhat
Ankara Eğitim ve Araştırma Hastanesi, Enfeksiyon Hastalıkları ve Klinik Mikrobiyoloji Kliniği, Ankara, Türkiye.
Mikrobiyol Bul. 2010 Oct;44(4):553-60.
Tuberculin skin test (TST) has been used effectively for a long time, despite inherent sensitivity and specificity limitations. Patients with a positive TST without active tuberculosis are identified as having latent tuberculosis infection. Identifying patients with latent tuberculosis infection with this test is an important part of control of the disease. A whole-blood inferferon gamma (IFN-γ) assay, the Quantiferon TB Gold test (QTG; Cellestis, Australia) which is a promising in vitro diagnostic test for the identification of latent tuberculosis infection (LTBI), has potential advantages over the TST. This test includes Myobacterium tuberculosis specific ESAT- 6 and CFP-10 antigens. The aim of this study was to compare the results obtained by QTG and TST in active tuberculosis (TB) patients, close contacts of patients, health care workers and tuberculosis laboratory personel. Twenty-six patients with active pulmonary TB, 6 close contacts of those patients, 11 health care workers with contact to TB patients and 8 TB reference laboratory personnel were included in the study. Prior to administration of the TST, blood samples were drawn from each participant for QTG test. All subjects were asked for BCG vaccination history and examined for a BCG scar. All individuals had a BCG scar. The QTG assay was performed in whole blood samples according to manufacturer's instructions. The agreement between TST and QTG was measured with kappa statistical analysis. In active TB patients (true-infected cases) TST (PPD) positivity was found 34.6% (9/26) while QTG positivity was 65.3% (17/26). Although the positivity rate was higher in QTG test, this difference was not found statistically significant (p > 0.001). TST and QTG positivity rates for health care workers, close house contact of TB patients and TB laboratory staff were as follows, respectively; 36% (4/11) and 27% (3/11); 16.6% (1/6) and 83% (5/6); 37.5% (3/8) and 75% (6/8). The mean PPD diameter was 11 mm in QTG negative group and 14 mm in QTG positive group with a statistically significant difference (p < 0.001). However, there was no statistical significance between QTG positive and negative groups by means of age (p ≥ 0.05) and gender (p < 0.001). In conclusion, QTG assay was superior to TST in its ability to detect LTBI and active TB infection, not to be affected with BCG vaccination, to discriminate responses due to non-tuberculous mycobacteria, and to avoid variability and subjectivity associated with application and reading the TST. Besides, QTG assay needs only one visit to the test unit. However, its being expensive than TST and requirement for special equipments and skilled laboratory personnel, are among the disadvantages of QTG assay.
结核菌素皮肤试验（TST）长期以来一直被有效使用，尽管其存在固有的敏感性和特异性局限性。结核菌素皮肤试验结果呈阳性但无活动性结核病的患者被判定为患有潜伏性结核感染。通过该试验识别潜伏性结核感染患者是疾病控制的重要环节。全血干扰素γ（IFN-γ）检测，即结核菌素金标定量试验（QTG；澳大利亚Cellestis公司），是一种用于识别潜伏性结核感染（LTBI）的很有前景的体外诊断试验，与结核菌素皮肤试验相比具有潜在优势。该检测包括结核分枝杆菌特异性早期分泌抗原靶6（ESAT-6）和培养滤液蛋白10（CFP-10）抗原。本研究的目的是比较QTG和TST在活动性结核病（TB）患者、患者密切接触者、医护人员及结核病实验室人员中的检测结果。本研究纳入了26例活动性肺结核患者、6例这些患者的密切接触者、11例接触过结核病患者的医护人员以及8名结核病参比实验室人员。在进行结核菌素皮肤试验之前，采集每位参与者的血样进行QTG检测。询问所有受试者的卡介苗接种史并检查卡介苗瘢痕。所有个体均有卡介苗瘢痕。根据制造商的说明，在全血样本中进行QTG检测。采用kappa统计分析来衡量TST和QTG之间的一致性。在活动性结核病患者（真正感染病例）中，结核菌素皮肤试验（PPD）阳性率为34.6%（9/26），而QTG阳性率为65.3%（17/26）。虽然QTG检测的阳性率更高，但差异无统计学意义（p>0.001）。医护人员、结核病患者的密切家庭接触者以及结核病实验室工作人员的TST和QTG阳性率分别如下：36%（4/11）和27%（3/11）；16.6%（1/6）和83%（5/6）；37.5%（3/8）和75%（6/8）。QTG阴性组的平均PPD直径为11mm，QTG阳性组为14mm，差异有统计学意义（p<0.001）。然而，QTG阳性和阴性组在年龄（p≥0.05）和性别（p<0.001）方面无统计学差异。总之，QTG检测在检测潜伏性结核感染和活动性结核感染的能力方面优于结核菌素皮肤试验，不受卡介苗接种影响，能区分非结核分枝杆菌引起的反应，且避免了与结核菌素皮肤试验的应用和判读相关的变异性和主观性。此外，QTG检测仅需到检测单位一次就诊。然而，其比结核菌素皮肤试验昂贵，且需要特殊设备和技术熟练的实验室人员，这些都是QTG检测的缺点。
