Immediate Incubation Reduces Indeterminate Results for QuantiFERON-TB Gold In-Tube Assay
Immediate Incubation Reduces Indeterminate Results for QuantiFERON-TB Gold In-Tube Assay
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DOI：
10.1128/jcm.00482-10
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发表时间：
2010-08-01
影响因子：
9.4
通讯作者：
Banaei, Niaz
中科院分区：
文献类型：
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作者：
Herrera, Victor;Yeh, Ellen;Banaei, Niaz
在体外，干扰素释放试验(IGRAs)越来越多地被用作传统结核菌素皮肤试验的替代方法，用于诊断潜在的结核分枝杆菌感染。在斯坦福医院和诊所大规模实施医护人员筛查计划之前，对量子铁结核金试管试验(QFT-IT)进行的评估显示，一个关键的分析前因素影响了结果。我们发现，孵化延迟显著增加了不确定结果的出现频率。在这项研究中，来自健康志愿者的样本进行了QFT-IT，复制管在37℃下立即孵育或在室温下延迟6和12小时后孵育，立即孵育时没有看到不确定结果(0/41)。延迟孵育6h和12h的不确定结果分别为10%(2/20)(P=0.10)和17.1%(7/41)(P=0.01)。不确定结果的增加是由于延迟孵育6h(P=0.004)和12h(P<；0.001)无丝分裂管的平均值下降所致。培养即刻、延迟6小时和12小时阳性或阴性结果的符合率分别为77.8%(14/18)和79.4%(27/34)。随后在我们对14,830名医护人员的筛查计划中实施即时潜伏期程序，在12个月的时间内产生了0.36%的不确定结果，比报道的QFT-IT的5%至40%有显著改善。我们的结论是，即时孵育QFT-IT管是减少不确定结果的有效方法。孵育延迟对QFT-IT准确度的影响尚待确定。
In vitro gamma interferon release assays (IGRAs) are increasingly used as an alternative to the traditional tuberculin skin test for the diagnosis of latent Mycobacterium tuberculosis infection. Evaluation of the Quanti-FERON-TB Gold in-tube assay (QFT-IT) prior to large-scale implementation at the Stanford Hospital and Clinics for a health care worker screening program revealed a critical preanalytical factor affecting the results. We found that incubation delay significantly increased the frequency of indeterminate results. In this study, QFT-IT was performed with samples from healthy volunteers, and replicate tubes were incubated at 37 degrees C either immediately or after a delay at room temperature for 6 and 12 h. No indeterminate results (0/41) were seen when the assay was performed with immediate incubation. Incubation delays of 6 and 12 h yielded indeterminate results at rates of 10% (2/20) (P = 0.10) and 17.1% (7/41) (P = 0.01), respectively. The increased rate of indeterminate results was due to a decrease in the mean values for the mitogen-nil tubes when incubation was delayed for 6 h (P = 0.004) and 12 h (P < 0.001). The rates of concordance of positive or negative results obtained following immediate incubation and following 6- and 12-h delays were 77.8% (14/18) and 79.4% (27/34), respectively. Subsequent implementation of the immediate incubation procedure in our screening program for 14,830 health care workers yielded an indeterminate result rate of 0.36% over a period of 12 months, a significant improvement over the reported rates of 5 to 40% for QFT-IT. We conclude that immediate incubation of QFT-IT tubes is an effective way to minimize indeterminate results. The effect of incubation delay on the accuracy of QFT-IT remains to be determined.