Emergency Department, Edinburgh Royal Infirmary, 51 Little France Crescent, Edinburgh, EH16 4SA UK.
Emerg Med J. 2012 Dec;29(12):969-71. doi: 10.1136/emermed-2011-201037. Epub 2012 Feb 14.
To assess if measurement of either C reactive protein (CRP) or erythrocyte sedimentation rate (ESR) individually has an equivalent diagnostic value to measurement of both in identifying orthopaedic infection as the cause of paediatric atraumatic limb pain.
Emergency department of a paediatric teaching hospital.
Retrospective study of case notes for patients attending the emergency department with a complaint of atraumatic limb pain and in whom both ESR and CRP were measured at the time of presentation. Laboratory results at the time of presentation were recorded along with the final diagnosis. Receiver operating characteristic (ROC) curves were created using the data and the optimum cut-off values for each of ESR and CRP were derived using the point of best trade off between sensitivity and specificity. Likelihood ratios for ESR and CRP individually and in combination were calculated.
259 patients were included in the study, of whom 17 were considered to have an orthopaedic infection. ROC curves revealed the best results were obtained using cut-off values of CRP >7 and ESR >12. The combination of a CRP >7 and an ESR >12 gave the best positive likelihood ratio at 6.26 (likelihood ratio 5.34 (CRP >7) vs 2.57 (ESR >12)). For ruling out disease, the combination of CRP ≤7 and ESR ≤12 also outperformed either variable individually (negative likelihood ratio 0.09 (CRP ≤7 and ESR ≤12) vs 0.34 (CRP ≤7) vs 0.18 (ESR ≤12)).
Measurement of both CRP and ESR should be considered an important aid in the investigation of atraumatic limb pain.
评估单独测量 C 反应蛋白（CRP）或红细胞沉降率（ESR）是否与同时测量两者具有同等的诊断价值，以确定骨科感染是否为儿童无创伤性肢体疼痛的病因。
儿科教学医院的急诊部。
回顾性研究了在急诊部就诊的以无创伤性肢体疼痛为主要症状且就诊时同时测量了 ESR 和 CRP 的患者的病历。记录了就诊时的实验室结果以及最终诊断。使用数据创建了接收器操作特征（ROC）曲线，并使用灵敏度和特异性之间最佳权衡的点确定了 ESR 和 CRP 的最佳截断值。计算了 ESR 和 CRP 单独和组合的似然比。
共纳入 259 例患者，其中 17 例被认为患有骨科感染。ROC 曲线显示，使用 CRP >7 和 ESR >12 的截断值可获得最佳结果。CRP >7 和 ESR >12 的组合具有最佳的阳性似然比，为 6.26（似然比 5.34（CRP >7）与 2.57（ESR >12））。对于排除疾病，CRP ≤7 和 ESR ≤12 的组合也优于任何单个变量（阴性似然比 0.09（CRP ≤7 和 ESR ≤12）与 0.34（CRP ≤7）与 0.18（ESR ≤12））。
测量 CRP 和 ESR 均应被视为无创伤性肢体疼痛调查的重要辅助手段。
