Clinical Biochemistry Unit, Alfred Pathology Service, Prahran, Victoria, Australia; Central Clinical School, Monash University, Prahran, Victoria, Australia.
Clinical Biochemistry Unit, Alfred Pathology Service, Prahran, Victoria, Australia.
Clin Biochem. 2013 Aug;46(12):979-982. doi: 10.1016/j.clinbiochem.2013.04.016. Epub 2013 Apr 26.
Troponin point of care tests have been found to have inferior sensitivity to laboratory based tests, when either the 10% CV or the 99 th percentile of a healthy population is used as the cut-off. In a prospective study we evaluated a decreased cut-off in the detection of cardiac injury.
We compared 2 point of care assays (i-stat, Abbott Diagnostics and AQT 90, Radiometer) for troponin I with a laboratory assay for troponin I (ARCHITECT STAT troponin-I assay, Abbott Diagnostics), previously evaluated for diagnosis of acute coronary syndrome (ACS). We used the published 99 th percentile and a value that was 50% of that. We investigated these tests in a convenience sample of 195 patients presenting to a suburban hospital. We used chi-square tests for the comparison and a P<0.05 as significant. Clinical outcomes were obtained for patients with elevated levels of the laboratory assay.
At the 99 th percentile both assays did only detect cardiac injury in a percentage of true positives compared to the laboratory test (34 and 51%) with a significant rate of false negative values (19.6 and 14.9%). Using a decreased cut-off (50% of 99 th percentile) increased detection of true positives (to 80.9 and 76.5%) with an acceptable rate of false positive results (7.3 and 7.1%) significantly (P<0.01). Clinical review showed POC tests missed 6 of 13 patients with confirmed AMI (a sensitivity of 46%) and that a lower cut-off allowed them to detect all (for the i-stat) or most (4 of 6 for the AQT) of them.
We believe that we have described in this study a way to improve the sensitivity of point of care assays for troponin that allows us to identify additional patients without losing the specificity required to identify appropriate patients for discharge from the emergency department.
当使用 10%CV 或健康人群的第 99 百分位数作为截断值时，肌钙蛋白即时检测的敏感性发现低于基于实验室的检测。在一项前瞻性研究中，我们评估了降低截断值在检测心脏损伤中的作用。
我们比较了两种即时检测（i-stat，雅培诊断公司和 AQT90，雷度米特公司）的肌钙蛋白 I 与实验室检测（ARCHITECT STAT 肌钙蛋白-I 检测，雅培诊断公司），该实验室检测先前用于诊断急性冠状动脉综合征（ACS）。我们使用了已发表的第 99 百分位数和该值的 50%。我们在一家郊区医院的便利样本中研究了这些检测。我们使用卡方检验进行比较，以 P<0.05 为有统计学意义。对于实验室检测水平升高的患者，我们获得了临床结局。
在第 99 百分位数时，与实验室检测相比，两种检测在真阳性百分比上都只检测到心脏损伤（分别为 34%和 51%），且假阴性率显著（分别为 19.6%和 14.9%）。使用降低的截断值（99 百分位数的 50%），增加了真阳性的检出率（分别为 80.9%和 76.5%），同时假阳性率可接受（分别为 7.3%和 7.1%），差异具有统计学意义（P<0.01）。临床回顾显示，POC 检测漏诊了 13 例确诊为 AMI 的患者中的 6 例（敏感性为 46%），且降低截断值使它们能够检测到所有（对于 i-stat）或大多数（对于 AQT，为 6 例中的 4 例）患者。
我们认为，在这项研究中，我们描述了一种提高即时检测肌钙蛋白敏感性的方法，使我们能够识别更多的患者，而不会失去从急诊科出院所需的适当患者的特异性。
