McKeating Cara, White P Lewis, Posso Raquel, Palmer Michael, Johnson Elizabeth, McMullan Ronan
Department of Microbiology, Belfast Health and Social Care Trust, The Royal Hospitals, Belfast, UK.
Mycology Regional Reference Unit, University Hospital of Wales, Cardiff, UK.
J Clin Pathol. 2018 May;71(5):420-424. doi: 10.1136/jclinpath-2017-204692. Epub 2017 Sep 28.
Although treatment for candidaemia is time critical, culture-based tests prolong turnaround times and may promote underdiagnosis. Non-culture-based tests have the potential to overcome these difficulties but are in limited clinical use. The aim of this work was to undertake an initial evaluation of two non-culture-based tests for diagnosis of candidaemia.
Patients with candidaemia were identified prospectively over a 4-month period. Sera drawn from case (candidaemic) and control (non-candidaemic) patients on the same day as the positive blood culture were tested with both the Renishaw RenDx Fungiplex test and a commercial β-d-glucan (BDG) assay (Fungitell, Associates of Cape Cod). Sensitivity and specificity were calculated independently and in combination, using paired blood culture as the reference standard.
There were 10 eligible case patients and 39 negative controls. PCR sensitivity and specificity were found to be 44.4% (95% CI 18.9% to 73.3%) and 87.2% (72.8% to 94.8%), respectively. BDG sensitivity and specificity were 80% (47.9% to 95.4%) and 89.7% (75.9% to 96.5%), respectively. When combining PCR and BDG, sensitivity was 90% (95% CI 57.4% to 100%) and specificity was 79.5% (64.2% to 89.5%). When two sequential specimens were tested, PCR sensitivity increased to 60% (95% CI 31.2% to 83.3%) and BDG sensitivity to 90% (54.7% to 100%).
A combination of tests, or a single test at multiple time points, may be preferable to relying on one test at a single time point. This should be accounted for in design of future diagnostic accuracy studies of tests for invasive candidosis.
尽管念珠菌血症的治疗对时间要求严格，但基于培养的检测会延长周转时间并可能导致诊断不足。非基于培养的检测有潜力克服这些困难，但临床应用有限。这项工作的目的是对两种用于诊断念珠菌血症的非基于培养的检测进行初步评估。
在4个月的时间里前瞻性地识别念珠菌血症患者。在血培养阳性当天从病例（念珠菌血症）和对照（非念珠菌血症）患者采集的血清，同时用雷尼绍RenDx真菌多重检测法和一种商业β - d - 葡聚糖（BDG）检测法（Fungitell，科德角联合公司）进行检测。以配对血培养作为参考标准，独立计算并综合计算敏感性和特异性。
有10例符合条件的病例患者和39例阴性对照。发现PCR的敏感性和特异性分别为44.4%（95%可信区间18.9%至73.3%）和87.2%（72.8%至94.8%）。BDG的敏感性和特异性分别为80%（47.9%至95.4%）和89.7%（75.9%至96.5%）。当将PCR和BDG联合使用时，敏感性为90%（95%可信区间57.4%至100%），特异性为79.5%（64.2%至89.5%）。当检测两个连续样本时，PCR敏感性增至60%（95%可信区间31.2%至83.3%），BDG敏感性增至90%（54.7%至100%）。
联合检测或在多个时间点进行单次检测，可能比在单个时间点依赖单一检测更可取。这在未来侵袭性念珠菌病检测诊断准确性研究的设计中应予以考虑。
