Zhuo Ran, Cho Joanne, Qiu YuanYuan, Parsons Brendon D, Lee Bonita E, Chui Linda, Freedman Stephen B, Pang Xiaoli
Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, Alberta, Canada.
Department of Pediatrics, University of Alberta, Edmonton, Alberta, Canada.
J Clin Virol. 2017 Nov;96:94-98. doi: 10.1016/j.jcv.2017.10.003. Epub 2017 Oct 9.
It is important to understand the diagnostic accuracy of multiplex panels such as the Luminex xTAG Gastrointestinal Pathogen Panel (GPP) as they are increasingly employed for routine diagnostics worldwide. Recent evaluations in our laboratory identified lower detection rates of norovirus genogroup II (NoV GII) using GPP compared to our laboratory-developed RT-qPCR, Gastroenteritis Virus Panel (GVP).
To characterize the cases of discordant NoV GII results between GPP and GVP and determine the sensitivity of the two assays for specific NoV GII genotypes.
We genotyped discordant NoV GII strains identified in stool samples or rectal swabs collected prospectively from a cohort of children with acute gastroenteritis between December 2014 and July 2016. The sensitivities of GVP and GPP for NoV GII were compared by analyses of GVP threshold cycle (Ct) and ten-fold serial dilutions of positive samples of various NoV GII genotypes.
All discordant samples (63/607) were NoV GII positive by GVP but negative by GPP. Twenty-two were successfully genotyped, fourteen of which were NoV GII genotype 2 (GII.2). The median Ct value of concordant positives was lower than that of discordant results (19.8 vs. 33.7; P<0.0001). GVP was 10 and at least 10,000-fold more sensitive than GPP in detecting NoV GII.3 and GII.2, respectively, but has similar sensitivity for NoV GII.4. Discordant GII.2 variant differed genetically from concordant GII.2 variants.
GPP has lower sensitivity to detect NoV GII.2 than GVP and its use may lead to undetected cases clinically, and an underestimation of NoV disease burden at the population level.
了解诸如Luminex xTAG胃肠道病原体检测板（GPP）等多重检测板的诊断准确性很重要，因为它们在全球范围内越来越多地用于常规诊断。我们实验室最近的评估发现，与我们实验室开发的逆转录定量聚合酶链反应（RT-qPCR）肠胃炎病毒检测板（GVP）相比，使用GPP检测诺如病毒II基因组（NoV GII）的检出率较低。
对GPP和GVP之间NoV GII结果不一致的病例进行特征分析，并确定两种检测方法对特定NoV GII基因型的敏感性。
我们对2014年12月至2016年7月期间从一组急性肠胃炎儿童中前瞻性收集的粪便样本或直肠拭子中鉴定出的不一致NoV GII菌株进行基因分型。通过分析GVP阈值循环（Ct）和各种NoV GII基因型阳性样本的十倍系列稀释液，比较GVP和GPP对NoV GII的敏感性。
所有不一致的样本（63/607）通过GVP检测为NoV GII阳性，但通过GPP检测为阴性。22个样本成功进行了基因分型，其中14个为NoV GII基因型2（GII.2）。一致性阳性样本的Ct值中位数低于不一致结果的Ct值中位数（19.8对33.7；P<0.0001）。在检测NoV GII.3和GII.2时，GVP分别比GPP敏感10倍和至少10000倍，但对NoV GII.4的敏感性相似。不一致的GII.2变体在基因上与一致性GII.2变体不同。
GPP检测NoV GII.2的敏感性低于GVP，使用GPP可能导致临床漏诊病例，并低估人群水平上的NoV疾病负担。
