参考测量程序在血清肌酐测定正确度验证中的应用

Application of reference measurement procedure in trueness verification of serum ceatinine assays

目的分析和讨论目前肌酐(Cr)常规测定和校准中可能遇到的问题及参考测量程序在正确度验证中的作用。方法使用血清Cr参考测量程序同位素稀释液相色谱质谱法,以及市售4种Cr酶法试剂和3种苦味酸法试剂组成的7种测定系统同时测定正确度验证样品、质控品和受干扰标本,考察不同性质样品在不同分析系统上的表现。结果对于正确度验证样品201211,4种酶法系统与参考方法测定值的相对偏差分别为13.2%、-5.2%、-4.3%和10.2%,3种苦味酸法系统的相对偏差分别为5.0%、28.0%、29.5%。对于正确度验证样品201212,酶法系统的相对偏差分别为3.8%、1.4%、-2.0%和3.0%,苦味酸法系统的相对偏差分别为3.7%、6.0%和10.1%。对于疑似受干扰标本,酶法系统的测定均值为66.40μmol/L,苦味酸法系统测定均值为102.29μmol/L。结论对低Cr浓度的样品,苦味酸法更易受到特异性等因素的干扰。酶法则可能受到药物、还原性等物质的特殊干扰。应正确运用参考测量程序,重视Cr测定的特异性和干扰问题。

Objective：To analyze and discuss the technical issues in serum creatinine assays and the role of reference measurement procedure for trueness verification. Methods：The trueness verification materials, quality control samples and the disturbed serum samples were measured by isotope dilution liquid chromatography tandem mass spectrometry （ID LC/MS/MS） method and 7 routine creatinine assays, including 4 enzyme methods and 3 Jaffe methods. The performance of each analytical system was assessed. Results：For the sample 201211 of trueness verification with low creatinine level, the relative biases were 13.2%, -5.2%, -4.3% and 10.2% for the 4 enzyme method respectively, and 5.0%, 28.0%, 29.5% for the 3 Jaffe methods respectively. For the sample 201212 of trueness verification with high creatinine level, the relative biases were 3.8%, 1.4%, -2% and 3.0% by 4 enzyme methods respectively, and 3.7%, 6.0% and 10.1% by 3 Jaffe methods are respectively. The average value of a patient serum with unspecific interference was 66.40 μmol/L in enzyme analysis systems and 102.29 μmol/L in Jaffe analysis systems. Conclusion：The specificity of Jaffe method is susceptible to be disturbed for the samples with low level of creatinine. The enzyme method may be affected by certain pharmaceuticals and reducing chemicals. The attention for the specificity and interference in creatinine measurement should be paid and the reference measurement procedure should be performed properly.