Costa José Torres, Silva Rui, Sá Raul, Cardoso Maria João, Ribeiro Carla, Nienhaus Albert
Occupational Health Division (Hospital São João), Allergy and Clinical Immunology Division (Hospital São João), Faculty of Medicine, Porto University.
Rev Port Pneumol. 2010 Mar-Apr;16(2):211-21.
Healthcare workers (HCWs) have an increased risk of tuberculosis (TB). Screening for latent tuberculosis infection and active TB is therefore essential in infection control programs. Tuberculin skin test (TST) and Interferon -gamma Release Assay (IGRA) were used simultaneously in 1686 HCWs between May 2007 and April 2009. A chest X -ray was performed in order to exclude active TB when TST was >or=10mm or IGRA was positive and in HCWs with TB contact or symptoms. IGRA was positive in 33.1% and TST was >10mm in 78.3% of the HCWs. The proportion of positive IGRA results increased with the TST diameter. In those with a TST >15mm, 49.2% were IGRA positive. TST was more than twice as often positive than the IGRA. Therefore, TST+/IGRA- results were more often observed than concordant negative or positive results. In none of the HCWs with a TST+/IGRA- result active TB was diagnosed during the study period. Repeated BCG vaccination increased the number of TST+/IGRA- discordance. The smaller the interval after BCG vaccination, the higher was the TST+/IGRA- discordance. In the screened HCWs population, active TB was diagnosed in 9. At the time of diagnosis TST and IGRA were positive in all active TB cases. The study period covers 24 months, therefore the average annual incidence rate was 268/100 000. TB burden in HCWs in Portugal is high. Considering the limitations that TST and IGRA present, the best solution seems to be the use of both, using the IGRA higher specificity for confirming a positive TST, taking advantage of the best characteristics of each test.
医护人员感染结核病（TB）的风险增加。因此，在感染控制项目中筛查潜伏性结核感染和活动性结核病至关重要。2007年5月至2009年4月期间，对1686名医护人员同时进行了结核菌素皮肤试验（TST）和干扰素-γ释放试验（IGRA）。当TST≥10mm或IGRA呈阳性时，以及在有结核病接触史或症状的医护人员中，进行胸部X线检查以排除活动性结核病。33.1%的医护人员IGRA呈阳性，78.3%的医护人员TST>10mm。IGRA阳性结果的比例随TST直径增加而升高。在TST>15mm的人群中，49.2%的IGRA呈阳性。TST呈阳性的频率是IGRA的两倍多。因此，TST+/IGRA-结果比一致的阴性或阳性结果更常见。在研究期间，没有一名TST+/IGRA-结果的医护人员被诊断为活动性结核病。重复接种卡介苗增加了TST+/IGRA-不一致的数量。卡介苗接种后间隔时间越短，TST+/IGRA-不一致性越高。在筛查的医护人员群体中，有9人被诊断为活动性结核病。在诊断时，所有活动性结核病例的TST和IGRA均呈阳性。研究期为24个月，因此年平均发病率为268/10万。葡萄牙医护人员的结核病负担很高。考虑到TST和IGRA存在的局限性，最佳解决方案似乎是同时使用两者，利用IGRA更高的特异性来确认TST阳性，充分发挥每种检测方法的最佳特性。
