Alvarez-León Eva Elisa, Espinosa-Vega Elizabeth, Santana-Rodríguez Evora, Molina-Cabrillana Jesús M, Pérez-Arellano Jose Luis, Caminero Jose Antonio, Serrano-Aguilar Pedro
Complejo Hospitalario Universitario Insular Materno-Infantil, Las Palmas, Gran Canaria, Spain.
Infect Control Hosp Epidemiol. 2009 Sep;30(9):876-83. doi: 10.1086/598519.
The risk of latent tuberculosis (LTBI) in healthcare workers (HCWs) is high. Until recently, the tuberculin skin test (TST) was the only diagnostic test available for Mycobacterium tuberculosis infection. A new enzyme-linked immunosorbent assay test, the QuantiFERON-TB Gold (QFT-G) test, was recommended by the US Centers for Disease Control and Prevention as an alternative test for the diagnosis of LTBI in HCWs. The purpose of our study was to compare the TST and the QFT-G test in Spanish HCWs in order to improve procedures for the detection of LTBI.
A cross-sectional study with blinded comparison of TST and QFT-G test results was carried out among 134 HCWs at an 800-bed Spanish university hospital. The level of interferon-gamma production stimulated by the QFT-G test was measured. A concentration of at least 0.35 IU/mL was considered a positive result. An induration of at least 5 mm in non-BCG-vaccinated or at least 15 mm in BCG-vaccinated HCWs for the TST was considered positive.
Of the 134 HCWs included (mean age, 33.4 years; 101 [75.4%] women; 47 [35.1%] BCG vaccinated), the LTBI prevalence diagnosed with any test was 11.2% (95% confidence interval, 6.6%-18.1%), with the TST was 8.96%, and with the QFT-G test was 5.97% (nonsignificant differences). The QFT-G test value was higher in subjects with TST induration of at least 15 mm than in subjects with TST induration of less than 15 mm (P < .001). Overall agreement between the results of the two tests was found in 94% of HCWs (kappa = 0.56), but agreement was only 59% in HCWs who had a positive result for both tests. Disagreement was present in the results found for 5% of HCWs.
Few studies have compared both tests in populations with high M. tuberculosis exposure but low BCG vaccination prevalence. Agreement between both tests is high, especially among negative results. Studies are needed to clarify the reasons for disagreement and to establish the best TST and QFT-G test cutoff point.
医护人员发生潜伏性结核病（LTBI）的风险很高。直到最近，结核菌素皮肤试验（TST）仍是唯一可用于诊断结核分枝杆菌感染的检测方法。一种新的酶联免疫吸附试验，即全血γ干扰素释放试验（QFT-G），被美国疾病控制与预防中心推荐作为诊断医护人员LTBI的替代检测方法。我们研究的目的是比较西班牙医护人员中TST和QFT-G试验，以改进LTBI的检测程序。
在一家拥有800张床位的西班牙大学医院对134名医护人员进行了一项横断面研究，对TST和QFT-G试验结果进行盲法比较。测量QFT-G试验刺激产生的γ干扰素水平。浓度至少为0.35 IU/mL被视为阳性结果。对于TST，未接种卡介苗的医护人员硬结至少5 mm或接种卡介苗的医护人员硬结至少15 mm被视为阳性。
纳入的134名医护人员（平均年龄33.4岁；101名[75.4%]为女性；47名[35.1%]接种了卡介苗）中，任何检测方法诊断出的LTBI患病率为11.2%（95%置信区间，6.6%-18.1%），TST诊断出的患病率为8.96%，QFT-G试验诊断出的患病率为5.97%（差异无统计学意义）。TST硬结至少15 mm的受试者的QFT-G试验值高于TST硬结小于15 mm的受试者（P <.001）。94%的医护人员两种检测结果总体一致（kappa = 0.56），但两种检测结果均为阳性的医护人员中一致性仅为59%。5%的医护人员检测结果存在不一致。
很少有研究在结核分枝杆菌暴露率高但卡介苗接种率低的人群中对这两种检测方法进行比较。两种检测方法之间的一致性很高，尤其是在阴性结果中。需要开展研究以阐明不一致的原因，并确定最佳的TST和QFT-G试验临界值。
