Rothman Institute at Thomas Jefferson University, 925 Chestnut Street, 5th Floor, Philadelphia, PA 19107, USA.
Clin Orthop Relat Res. 2012 Jan;470(1):54-60. doi: 10.1007/s11999-011-1991-y.
C-reactive protein (CRP) serum assays are a standard element of the diagnostic workup for periprosthetic joint infection (PJI). However, because CRP is a marker for systemic inflammation, this test is not specific to PJI.
QUESTIONS/PURPOSES: Our purpose was to assess whether synovial fluid and serum assays alone could differentiate between infected and uninfected revision knee arthroplasties and to determine which of these methods had the greatest diagnostic accuracy.
We collected synovial fluid specimens from 66 patients undergoing revision total knee arthroplasty. Patients were judged uninfected or infected by standardized criteria. Synovial CRP levels were measured using an individual CRP assay (15 samples; 10 infected, five uninfected) and a multiplex immunoassay platform (59 samples; 25 infected, 34 uninfected). Results from preoperative standard serum CRP assays conducted were also collected (55 samples; 25 infected, 30 uninfected). Sensitivity, specificity, and receiver operating characteristic curve analyses were performed for each assay with a diagnosis of infection based on previously established criteria.
Synovial CRP concentrations differed between infected and uninfected joints in the multiplex and serum analyses. The area under the curve was 0.84 for the individual assay, 0.91 for the multiplex assay, and 0.88 for the serum CRP assay. Sensitivity and specificity were 70.0% and 100.0% for the individual enzyme-linked immunosorbent assay, 84.0% and 97.1% for the multiplex assay, and 76.0% and 93.3% for the serum CRP assay.
An assay measuring CRP in synovial fluid may be more accurate in diagnosing PJI than the standard serum CRP assay. We believe such an assay holds promise as a new diagnostic marker for PJI.
C 反应蛋白（CRP）血清检测是假体周围关节感染（PJI）诊断的标准项目。然而，由于 CRP 是全身炎症的标志物，因此该检测对 PJI 并不具有特异性。
问题/目的：我们旨在评估单独的关节液和血清检测是否能够区分感染和非感染的翻修膝关节置换术，并确定这些方法中哪一种具有最高的诊断准确性。
我们收集了 66 例接受翻修全膝关节置换术的患者的关节液标本。通过标准化标准判断患者是否感染。使用单个 CRP 检测（15 个样本；10 个感染，5 个非感染）和多重免疫分析平台（59 个样本；25 个感染，34 个非感染）测量关节液 CRP 水平。还收集了术前标准血清 CRP 检测的结果（55 个样本；25 个感染，30 个非感染）。对每种检测方法进行了基于先前建立的感染诊断标准的敏感性、特异性和接收者操作特征曲线分析。
在多重和血清分析中，感染和非感染关节的关节液 CRP 浓度存在差异。单个检测的曲线下面积为 0.84，多重检测的曲线下面积为 0.91，血清 CRP 检测的曲线下面积为 0.88。单个酶联免疫吸附试验的敏感性和特异性分别为 70.0%和 100.0%，多重检测的敏感性和特异性分别为 84.0%和 97.1%，血清 CRP 检测的敏感性和特异性分别为 76.0%和 93.3%。
测量关节液中 CRP 的检测可能比标准血清 CRP 检测更能准确诊断 PJI。我们认为，这种检测可能成为 PJI 的一种新的诊断标志物。
