Department of Trauma and Orthopaedics, North Bristol NHS Trust, Westbury on Trym, Bristol, UK
Department of Trauma and Orthopaedics, North Bristol NHS Trust, Westbury on Trym, Bristol, UK.
Emerg Med J. 2021 Sep;38(9):707-710. doi: 10.1136/emermed-2020-209842. Epub 2021 Mar 10.
Suspected septic arthritis is a common presentation to EDs. The underlying diagnosis is often non-infective pathology. Differentiating between aetiologies is difficult. A bedside test with high negative predictive value (NPV) may allow safe discharge of patients, reduce the time in the ED, hospital admission and associated costs. This study aims to evaluate the NPV of bedside leucocyte esterase (LE) in the assessment of these patients.
A prospective multicentre observational study of ED adult patients referred to orthopaedics with suspected native joint septic arthritis between October 2015 and April 2016. At three hospital sites in the Bristol region, the results of the LE test exposed to aspirated synovial fluid were recorded along with Gram stain, culture, haematinics and length of stay. A positive LE test was considered 2+ or 3+ leucocytes based on the test strip colour. Data were analysed to establish sensitivity, specificity, NPV and positive predictive value (PPV) against the gold standard 48-hour culture. We determined the potential number of inpatient bed-days that might be avoided using this bedside test.
Eighty patients underwent joint aspiration. Five cases had positive 48-hour culture. All (5/5) infected cases showed ≥2+ LE, sensitivity of 100% (95% CI 47.8% to 100%) while the Gram stain was positive in only one case (sensitivity 20%, 95% CI 0.51% to 71.6%). Twenty-three LE were read negative or 1+, all with negative 48-hour culture results, resulting in an NPV of 100% (95% CI 82.1% to 1.00%) for a negative LE test. Specificity of a positive LE test was 30.7% (95% CI 20.5% to 42.45%) with PPV of 8.77% (95% CI 7.64% to 10.1%). It was calculated that 57 orthopaedic bed-days could have potentially been saved by immediately discharging those with a negative LE test.
LE point-of-care testing for suspected septic arthritis of native joints has a high NPV. Implementation of LE may facilitate more rapid discharge of patients with negative results. This test has the potential to reduce diagnostic uncertainty and costs to the healthcare system.
疑似脓毒性关节炎是急诊科常见的就诊原因。潜在的诊断通常是非感染性病变。区分病因具有挑战性。具有高阴性预测值（NPV）的床边白细胞酯酶（LE）检测可能可以安全地让患者出院，减少急诊科停留时间、住院时间和相关费用。本研究旨在评估床边 LE 检测在评估这些患者中的 NPV。
本研究为 2015 年 10 月至 2016 年 4 月在布里斯托尔地区的三个医院，对疑似原发性关节脓毒性关节炎而转至骨科的急诊科成年患者进行前瞻性多中心观察性研究。记录暴露于关节抽吸液中的 LE 检测结果，以及革兰氏染色、培养、血液学检查和住院时间。根据测试条的颜色，将阳性 LE 检测结果定义为 2+或 3+白细胞。分析数据以确定与 48 小时培养的金标准相比，LE 检测的敏感性、特异性、NPV 和阳性预测值（PPV）。我们确定了使用这种床边检测可能避免的住院病床数量。
共 80 例患者进行了关节抽吸。5 例有 48 小时培养阳性。所有（5/5）感染病例均显示≥2+ LE，敏感性为 100%（95%CI 47.8%至 100%），而革兰氏染色仅在 1 例中阳性（敏感性 20%，95%CI 0.51%至 71.6%）。23 例 LE 检测结果为阴性或 1+，均为 48 小时培养结果阴性，NPV 为 100%（95%CI 82.1%至 1.00%）。阳性 LE 检测的特异性为 30.7%（95%CI 20.5%至 42.45%），阳性预测值为 8.77%（95%CI 7.64%至 10.1%）。计算得出，通过立即为 LE 检测结果阴性的患者办理出院，可以潜在节省 57 张骨科病床。
LE 即时检测对疑似原发性关节脓毒性关节炎具有较高的 NPV。实施 LE 检测可能有助于更快地为阴性结果的患者办理出院。该检测具有降低诊断不确定性和医疗保健系统成本的潜力。
