White P Lewis, Price Jessica S, Posso Raquel, Vale Lorna, Backx Matthijs
Mycology Reference Laboratory, Public Health Wales, Microbiology, Cardiff, UK
Mycology Reference Laboratory, Public Health Wales, Microbiology, Cardiff, UK.
J Clin Microbiol. 2020 Nov 18;58(12). doi: 10.1128/JCM.01006-20.
The objectives of this study were to evaluate the performance of the recently released IMMY galactomannan enzyme immunoassay (IMMY GM-EIA) when testing serum samples and to identify the optimal galactomannan index (GMI) positivity threshold for the diagnosis of invasive aspergillosis (IA). This was a retrospective case/control study, comprising 175 serum samples obtained from 131 patients, 35 of whom had probable or possible invasive fungal disease (IFD) as categorized using recently revised, internationally accepted definitions. The IMMY GM-EIA was performed following the manufacturer's instructions. Performance parameters were determined and receiver operator characteristic analysis was used to identify an optimal GMI threshold. Concordance with the Bio-Rad Ag assay (Bio Rad GM-EIA) and IMMY sona lateral flow assay was assessed. The median GMIs generated by the IMMY GM-EIA for samples originating from probable IA/IFD cases ( = 31), possible IFD ( = 4), and control patients ( = 100) were 0.61, 0.11, and 0.14, respectively, and were comparable to those of the Bio-Rad GM-EIA (0.70, 0.04, and 0.04, respectively). Overall qualitative observed sample agreement between the IMMY GM-EIA and Bio-Rad GM-EIA was 94.7%, generating a kappa statistic of 0.820. At a GMI positivity threshold of ≥0.5, the IMMY GM-EIA had a sensitivity and specificity of 71% and 98%, respectively. Reducing the threshold to ≥0.27 generated sensitivity and specificity of 90% and 92%, respectively. The IMMY GM-EIA provides a comparable alternative to the Bio-Rad GM-EIA when testing serum samples. Further prospective, multicenter evaluations are required to confirm the optimal threshold and associated clinical performance.
本研究的目的是评估最新发布的IMMY半乳甘露聚糖酶免疫测定法（IMMY GM-EIA）在检测血清样本时的性能，并确定用于诊断侵袭性曲霉病（IA）的最佳半乳甘露聚糖指数（GMI）阳性阈值。这是一项回顾性病例/对照研究，包括从131名患者中获得的175份血清样本，其中35名患者根据最近修订的国际公认定义被归类为可能或疑似侵袭性真菌病（IFD）。IMMY GM-EIA按照制造商的说明进行。确定性能参数，并使用受试者工作特征分析来确定最佳GMI阈值。评估了与Bio-Rad Ag测定法（Bio Rad GM-EIA）和IMMY sona侧流测定法的一致性。IMMY GM-EIA针对可能的IA/IFD病例（n = 31）、可能的IFD（n = 4）和对照患者（n = 100）的样本产生的GMI中位数分别为0.61、0.11和0.14，与Bio-Rad GM-EIA的结果（分别为0.70、0.04和0.04）相当。IMMY GM-EIA和Bio-Rad GM-EIA之间总体定性观察样本一致性为94.7%，kappa统计量为0.820。在GMI阳性阈值≥0.5时，IMMY GM-EIA的敏感性和特异性分别为71%和98%。将阈值降低到≥0.27时，敏感性和特异性分别为90%和92%。在检测血清样本时，IMMY GM-EIA为Bio-Rad GM-EIA提供了一种可比的替代方法。需要进一步进行前瞻性、多中心评估以确认最佳阈值和相关临床性能。
