心肌损伤生化标志物的质量规范。

Zaninotto M, Mion M, Altinier S, Forni M, Plebani M

Department of Laboratory Medicine, Chief, University-Hospital of Padova, Azienda Ospedaliera di Padova, Via Giustiniani, 2, Padova 35128, Italy.

Clin Chim Acta. 2004 Aug 2;346(1):65-72. doi: 10.1016/j.cccn.2004.02.035.

BACKGROUND

The current approach to the diagnosis and monitoring of myocardial damage, recognizes to biochemical markers, and in particular to troponins, a key role being well demonstrated that all elevated values were associated with a worsened prognosis. In 2001, the IFCC Committee on Standardization of Markers of Cardiac Damage published guidelines addressing the quality specifications for troponin assays in order to guarantee an analytical performance satisfying medical requirements and to standardize the quality of commercial methods. We describe how the application of quality specifications may be useful in daily practice, in order to provide advice to clinicians in the investigations of complex clinical cases of patients suffering from myocardial damage.

MATERIALS AND METHODS

The samples from three patients (cases 1-3) admitted to the hospital with symptoms suggestive of cardiac disease, showing high troponin I (cTnI) values not correlated with clinical condition, were investigated in order to verify the accuracy of the laboratory data. The standard of quality specifications related to assay specificity, imprecision and interferences were evaluated using different platforms for cTnI assays, carrying out imprecision profile and specific studies on more common interferents in immunoassays.

RESULTS

The obtained results allow us to demonstrate two cases of false-positive cTnI values attributable to a macrocomplex between a modified "in vivo" cTnI and immunoglobulin G (case 1) and to a presence of heterophilic antibodies affecting the RxL Dimension procedure (case 3). Instead, the accuracy of data obtained in case 2 was evidenced by the imprecision profile obtained in our laboratory and by the comparison of results between different laboratories using same platform.

CONCLUSIONS

The lack of standardization as well as the wide differences in the development of each assay give rise to major concerns regarding cTnI determinations. The laboratory must therefore check the compliance between the analytical characteristics of the method utilised against recommended quality specifications for a reliable understanding of the frequency of false-positive results as well as other serious analytical errors.

背景

目前心肌损伤的诊断和监测方法认可生化标志物，尤其是肌钙蛋白，其关键作用已得到充分证明，即所有升高的值都与预后恶化相关。2001年，国际临床化学和检验医学联合会（IFCC）心脏损伤标志物标准化委员会发布了关于肌钙蛋白检测质量规范的指南，以确保分析性能满足医学要求并规范商业方法的质量。我们描述了质量规范的应用在日常实践中如何有用，以便为临床医生在调查心肌损伤患者的复杂临床病例时提供建议。

材料与方法

对三名因疑似心脏病入院、肌钙蛋白I（cTnI）值高但与临床状况不相关的患者（病例1 - 3）的样本进行调查，以验证实验室数据的准确性。使用不同的cTnI检测平台评估与检测特异性、不精密度和干扰相关的质量规范标准，进行不精密度分析以及对免疫分析中更常见干扰物的特异性研究。

结果

获得的结果使我们能够证明两例假阳性cTnI值的情况，一例是由于修饰的“体内”cTnI与免疫球蛋白G之间形成大分子复合物（病例1），另一例是由于存在影响RxL Dimension程序的嗜异性抗体（病例3）。相反，病例2中获得的数据准确性通过我们实验室获得的不精密度分析以及使用相同平台的不同实验室之间的结果比较得到证明。