Seto Junji, Ahiko Tadayuki
Kekkaku. 2014 Apr;89(4):503-8.
To confirm the effectiveness of interferon-gamma release assays (IGRAs) in the tuberculosis (TB) contact investigation of elderly people, we analyzed the results of the QuantiFERON TB Gold in tube (QFT-3G) test, which is a commercially available IGRA.
We analyzed the results of the QFT-3G test in 2,420 subjects who were in close contact with TB patients. We investigated subjects with latent TB infection and those showing the onset of TB among the QFT-3G-positive subjects.
The QFT-3G-positive rate was 7.3% (95% confidence interval, 6.2%-8.3%). In addition, we demonstrated that the QFT-3G-positive rate increased with age (P < 0.001).
The QFT-3G-positive rate was high, particularly in elderly people (> or = 60 years), but the rate was significantly lower than the predicted prevalence of TB infection. Therefore, it was assumed that the QFT-3G test does not always provide a positive result, even in cases of subjects with a previous TB infection. Furthermore, data from the QFT-3G-positive subjects indicated that approximately one half of subjects aged 60-69 years, approximately one-third of those aged 70-79 years, and approximately one-quarter of those aged over 80 years have had recent TB infections. In conclusion, the results of the QFT-3G test in elderly people need to be carefully evaluated according to the contact situation with TB patients; nevertheless, the QFT-3G test is useful for the screening of latent TB infection in elderly people who were in close contact with TB patients.
为了证实γ-干扰素释放试验（IGRAs）在老年人结核病（TB）接触者调查中的有效性，我们分析了管内结核菌素释放试验（QFT-3G）的结果，这是一种市售的IGRA。
我们分析了2420名与结核病患者密切接触者的QFT-3G检测结果。我们调查了QFT-3G检测呈阳性的潜伏性结核感染患者和出现结核病发病的患者。
QFT-3G检测阳性率为7.3%（95%置信区间，6.2%-8.3%）。此外，我们证明QFT-3G检测阳性率随年龄增长而升高（P<0.001）。
QFT-3G检测阳性率较高，尤其是在老年人（≥60岁）中，但该率明显低于预测的结核感染患病率。因此，即使在既往有结核感染的受试者中，也认为QFT-3G检测并非总能得出阳性结果。此外，QFT-3G检测呈阳性的受试者的数据表明，60-69岁的受试者中约有一半、70-79岁的受试者中约有三分之一以及80岁以上的受试者中约有四分之一近期有结核感染。总之，老年人QFT-3G检测结果需要根据与结核病患者的接触情况进行仔细评估；然而，QFT-3G检测对于筛查与结核病患者密切接触的老年人中的潜伏性结核感染是有用的。
