Emergency Department, University Hospital Basel, Switzerland.
Department of Intensive Care, University Hospital Basel, Switzerland.
Swiss Med Wkly. 2021 Dec 7;151:w30103. doi: 10.4414/smw.2021.w30103. eCollection 2021 Dec 6.
To quantify mimics and chameleons of coronavirus disease 2019 (COVID-19), to analyse the diagnostic accuracy of the triage protocol, and to describe the resulting groups of mimics and chameleons - including their presenting symptoms and final diagnoses.
Diagnostic accuracy study including all adult patients tested for severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) at the emergency department of the University Hospital Basel, Switzerland during the first wave of pandemic in spring 2020. Diagnostic accuracy of triage was determined by calculating sensitivity, specificity, positive and negative predictive value, and positive and negative likelihood ratio. Triage to the group of suspected (+) and not suspected (-) COVID-19 was considered the index test, whereas a SARS-CoV-2 polymerase chain reaction test result was used as reference standard. Mimics were defined as false positives and chameleons as false negatives.
Of 2898 patients included in the analysis, 191 were true positives, 895 were false positives (mimics), 9 were false negatives (chameleons) and 1803 were true negatives. This resulted in a sensitivity of 0.95 (95% confidence interval [CI] 0.92-0.98) and a specificity of 0.67 (95% CI 0.65-0.69) for standardised triage. Among mimics, the main categories of final diagnoses were other infections (n = 513, 57.3%), cardiovascular diseases (excluding cerebrovascular) (n = 125, 14%), and non-infectious diseases of the respiratory system (n = 84, 9.4%). Fever (n = 357, 39.9% vs n = 104, 54.5%), cough (n = 466, 52.1% vs n = 126 66%), and smell or taste dysfunction (n = 60, 6.7% vs n = 24, 12.6%) were less frequently observed in mimics than in COVID-19 patients. Eight of nine COVID-19 chameleons presented with either nonspecific complaints (weakness and/or fatigue) or gastrointestinal symptoms.
The quantitative assessment of COVID-19 mimics and chameleons showed a high prevalence of mimics. Clinical differentiation between true positives and false positives is not feasible due to largely overlapping symptoms. Prevalence of chameleons was very low.
量化 2019 年冠状病毒病（COVID-19）的模拟病例和变色龙病例，分析分诊方案的诊断准确性，并描述模拟病例和变色龙病例的结果分组——包括其临床表现和最终诊断。
这是一项诊断准确性研究，纳入了 2020 年春季瑞士巴塞尔大学医院急诊科对所有接受严重急性呼吸综合征冠状病毒 2 型（SARS-CoV-2）检测的成年患者，以评估分诊方案的诊断准确性。通过计算敏感性、特异性、阳性和阴性预测值以及阳性和阴性似然比来确定分诊的诊断准确性。将分诊至疑似（+）和非疑似（-）COVID-19 患者的组视为指标测试，而 SARS-CoV-2 聚合酶链反应检测结果则作为参考标准。将假阳性定义为模拟病例，假阴性定义为变色龙病例。
在纳入分析的 2898 例患者中，191 例为真阳性，895 例为假阳性（模拟病例），9 例为假阴性（变色龙病例），1803 例为真阴性。这使得标准化分诊的敏感性为 0.95（95%置信区间[CI]0.92-0.98），特异性为 0.67（95% CI 0.65-0.69）。在模拟病例中，最终诊断的主要类别为其他感染（n=513，57.3%）、心血管疾病（不包括脑血管疾病）（n=125，14%）和非传染性呼吸系统疾病（n=84，9.4%）。发热（n=357，39.9% vs n=104，54.5%）、咳嗽（n=466，52.1% vs n=126，66%）和嗅觉或味觉障碍（n=60，6.7% vs n=24，12.6%）在模拟病例中比 COVID-19 患者中更少见。9 例 COVID-19 变色龙病例的临床表现均为非特异性症状（乏力和/或疲劳）或胃肠道症状。
COVID-19 模拟病例和变色龙病例的定量评估显示，模拟病例的患病率较高。由于症状大部分重叠，无法对真阳性和假阳性进行临床区分。变色龙病例的患病率非常低。
