Lee N, Rainer T H, Ip M, Zee B, Ng M H, Antonio G E, Chan E, Lui G, Cockram C S, Sung J J, Hui D S
Department of Medicine and Therapeutics, Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong.
Eur J Clin Microbiol Infect Dis. 2006 Dec;25(12):765-72. doi: 10.1007/s10096-006-0222-z.
The Centers for Disease Control and Prevention (CDC) recommend that SARS-coronavirus (SARS-CoV) testing be considered in epidemiologically high-risk patients hospitalized with community-acquired pneumonia (CAP) if no alternative diagnosis is identified after 72 h. The aim of this study was to identify routine laboratory variables that might indicate the need for SARS-CoV testing. Routine hematological/biochemical variables in patients with laboratory-confirmed SARS (2003) were compared with those in consecutive patients hospitalized June-December 2004 with radiologically confirmed CAP. Stepwise logistic regression analyses were performed to identify discriminating variables at baseline and by day 3 of hospitalization. Nasopharyngeal aspiration and antigen detection for influenza virus and respiratory syncytial virus using an immunofluorescence assay (IFA) were routinely performed in patients with CAP. Altogether, 181 patients with CAP (who remained undiagnosed by IFA) and 303 patients with SARS were studied. The mean intervals from symptom onset to admission were 3.1 and 2.8 days, respectively (p > 0.05). The etiological agent of CAP was identified retrospectively in only 39% of cases, the majority being bacterial pathogens. At baseline, age and absolute neutrophil count (ANC) were the only independent discriminating variables (p < 0.0001). Using a value of <4.4 x 10(9)/l as the cutoff for ANC, the sensitivity and specificity of ANC for discriminating SARS were 64 and 95%, respectively (AUC 0.90). By day 3 of hospitalization, age (p < 0.0001), change in ANC (p = 0.0003), and change in bilirubin (p = 0.0065) were discriminating variables. A model combining age <65 years, a change in ANC of >-3 x 10(9)/l, and a change in bilirubin of > or =0 mmol/l had a sensitivity of 43% and a specificity of 95% for SARS (AUC 0.90). There are only a few laboratory features (including lymphopenia) that clearly discriminate SARS from other causes of CAP. Nevertheless, when evaluating epidemiologically high-risk patients with CAP and no immediate alternative diagnosis, a low ANC on presentation along with poor clinical and laboratory responses after 72 h of antibiotic treatment may raise the index of suspicion for SARS and indicate a need to perform SARS-CoV testing.
美国疾病控制与预防中心（CDC）建议，如果在72小时后仍未确诊其他疾病，对于因社区获得性肺炎（CAP）住院的具有流行病学高风险的患者，应考虑进行严重急性呼吸综合征冠状病毒（SARS-CoV）检测。本研究的目的是确定可能提示需要进行SARS-CoV检测的常规实验室指标。将实验室确诊的SARS患者（2003年）的常规血液学/生化指标与2004年6月至12月期间因影像学确诊为CAP而住院的连续患者的指标进行比较。进行逐步逻辑回归分析，以确定基线时和住院第3天时的鉴别指标。对CAP患者常规进行鼻咽抽吸，并使用免疫荧光法（IFA）检测流感病毒和呼吸道合胞病毒的抗原。共研究了181例CAP患者（IFA检测未确诊）和303例SARS患者。从症状出现到入院的平均间隔时间分别为3.1天和2.8天（p>0.05）。仅在39%的病例中回顾性确定了CAP的病原体，大多数为细菌病原体。在基线时，年龄和绝对中性粒细胞计数（ANC）是仅有的独立鉴别指标（p<0.0001）。以<4.4×10⁹/L作为ANC的临界值，ANC鉴别SARS的敏感性和特异性分别为64%和95%（曲线下面积0.90）。到住院第3天时，年龄（p<0.0001）、ANC变化（p = 0.0003）和胆红素变化（p = 0.0065）为鉴别指标。一个结合年龄<65岁、ANC变化>-3×10⁹/L和胆红素变化≥0 mmol/L的模型对SARS的敏感性为43%，特异性为95%（曲线下面积0.90）。仅有少数实验室特征（包括淋巴细胞减少）能将SARS与其他CAP病因清楚地区分开来。然而，在评估具有流行病学高风险且无其他即时诊断的CAP患者时，就诊时ANC较低以及抗生素治疗72小时后临床和实验室反应不佳，可能会增加对SARS的怀疑指数，并提示需要进行SARS-CoV检测。
