Laboratory of Clinical Chemistry and Microbiology, IRCCS Galeazzi Orthopaedic Institute, Milan, Italy.
Laboratory of Clinical Chemistry and Microbiology, IRCCS Galeazzi Orthopaedic Institute, Milan, Italy; Laboratory of Clinical Microbiology, Department of Biomedical Sciences for Health, University of Milan, Milan, Italy.
Clin Microbiol Infect. 2016 Jun;22(6):555-60. doi: 10.1016/j.cmi.2016.03.020. Epub 2016 Mar 31.
Analysis of joint fluid is of paramount importance for the diagnosis of prosthetic joint infections. Different markers of inflammation and/or infection in joint fluid have been proposed for diagnosis of these infections. In this study we evaluated the performance of leucocyte esterase, C-reactive protein (CRP) and glucose assays in synovial fluids from 129 patients with septic (n = 27) or aseptic (n = 102) prosthetic joint failure. Samples were collected in serum tubes and centrifuged to limit the presence of corpuscle interfering with the assays. Determinations of leucocyte esterase and glucose were carried out by means of enzymatic colorimetric reactions performed on strips for urine analysis. Tests were considered positive when graded + or ++ whereas traces or absence of colour were considered negative. CRP was measured using an automated turbidimetric method and considered suggestive for infections when >10 mg/L. Leucocyte esterase was positive in 25/27 infected patients and negative in 99/102 not infected patients (sensitivity 92.6%, specificity 97.0%). CRP was higher than the threshold in 22/27 infected patients and in 6/102 not infected patients (sensitivity: 81.5%; specificity: 94.1%) whereas glucose showed the lowest sensitivity (77.8%) and specificity (81.4%), being negative in 21/27 and 19/102 infected and not infected patients, respectively. CRP led to a correct diagnosis in 19 of 22 patients with discordant esterase and glucose results. In conclusion, evaluation of leucocyte esterase, glucose and CRP may represent a useful tool for rapid diagnosis of prosthetic joint infections.
关节液分析对于假体关节感染的诊断至关重要。已经提出了关节液中不同的炎症和/或感染标志物用于这些感染的诊断。在这项研究中，我们评估了白细胞酯酶、C 反应蛋白（CRP）和葡萄糖测定在 129 例感染性（n=27）或无菌性（n=102）假体关节失败患者的关节液中的性能。样品收集在血清管中并离心，以限制对测定有干扰的细胞的存在。白细胞酯酶和葡萄糖的测定通过尿液分析条上的酶比色反应进行。当分级为+或++时，认为试验为阳性，而痕迹或无颜色则认为阴性。CRP 采用自动比浊法测定，当>10mg/L 时，认为提示感染。27 例感染患者中有 25 例白细胞酯酶阳性，102 例未感染患者中 99 例白细胞酯酶阴性（敏感性 92.6%，特异性 97.0%）。CRP 高于阈值的感染患者为 22/27 例，未感染患者为 6/102 例（敏感性：81.5%；特异性：94.1%），而葡萄糖的敏感性（77.8%）和特异性（81.4%）最低，分别在 21/27 例和 19/102 例感染和未感染患者中为阴性。CRP 在 22 例白细胞酯酶和葡萄糖结果不一致的患者中导致了 19 例正确的诊断。总之，白细胞酯酶、葡萄糖和 CRP 的评估可能是快速诊断假体关节感染的有用工具。
