Department of Laboratory Medicine and Pathology, University of Minnesota Medical School, Mayo Mail Code 134, 420 Delaware St. S.E, Minneapolis, MN, 55455, USA.
Infectious Diseases Diagnostic Laboratory, University of Minnesota Medical Center and Fairview Health System, Minneapolis, MN, USA.
Curr Microbiol. 2021 Aug;78(8):2956-2960. doi: 10.1007/s00284-021-02547-0. Epub 2021 Jun 3.
In our laboratory, the negative rapid group A streptococcal (GAS) antigen assays are backed up by the Solana® GAS Assay by Quidel instead of a Group A streptococcal throat culture. Another FDA cleared RT-PCR assay is the Xpert® Xpress Strep A, which detects Streptococcus pyogenes DNA, and is performed on the Cepheid GeneXpert instrument. Three hundred seventy-five positive and negative specimens were randomly selected from 5489 throat specimens that had been tested by the Solana® GAS Assay during January 2018 and were tested with the Xpress Strep A assay. A throat culture was also set up (sheep blood agar at 35 °C in 5% CO2). All beta-hemolytic streptococci were purified and identified by MALDI-TOF mass spectrometry. Of the 375 samples, 185 were positive by Solana® GAS Assay, and 187 were positive by the Xpress Strep A. The total agreement between the Solana® GAS Assay and the Xpert® Xpress Strep A was 99.5%. The agreement of the Xpert® Xpress Strep A assay with culture was 90.1%. The sensitivity and specificity for Xpress Strep A versus culture were 100% and 83.5%, respectively. The Xpert® Xpress Strep A assay's performance was equivalent to the Solana® GAS Assay, and was highly sensitive. The lower specificity was likely due to the Xpress Strep A assay having higher sensitivity as compared to throat culture.
在我们的实验室中，阴性快速 A 组链球菌（GAS）抗原检测由 Quidel 的 Solana® GAS 检测替代 A 组链球菌咽拭子培养。另一种获得 FDA 批准的实时 RT-PCR 检测是 Xpert® Xpress Strep A，它可检测化脓性链球菌 DNA，在 Cepheid GeneXpert 仪器上进行。从 2018 年 1 月使用 Solana® GAS 检测的 5489 例咽拭子标本中随机选择了 375 例阳性和阴性标本，并用 Xpress Strep A 检测进行检测。还建立了咽拭子培养（羊血琼脂在 35°C 和 5% CO2 下）。所有乙型溶血性链球菌均通过 MALDI-TOF 质谱进行纯化和鉴定。在 375 个样本中，Solana® GAS 检测有 185 个阳性，Xpress Strep A 有 187 个阳性。Solana® GAS 检测与 Xpert® Xpress Strep A 的总符合率为 99.5%。Xpert® Xpress Strep A 检测与培养的符合率为 90.1%。Xpress Strep A 对培养的敏感性和特异性分别为 100%和 83.5%。Xpert® Xpress Strep A 检测的性能与 Solana® GAS 检测相当，且具有很高的敏感性。特异性较低可能是由于 Xpress Strep A 检测的敏感性高于咽拭子培养。
