Binding Site Group Limited, 8 Calthorpe Road, Birmingham B15 1QT, United Kingdom.
Clin Biochem. 2013 Nov;46(16-17):1751-5. doi: 10.1016/j.clinbiochem.2013.07.014. Epub 2013 Jul 25.
Accurate measurement of IgG subclass (IgGSc) levels are essential to aid in the diagnosis of disease states such as primary immunodeficiencies. However, there is no single standardisation of nephelometric and turbidimetric assays for these analytes and two reference materials have been utilised. We expand on previous reports and present data from a multi-site analysis that both identifies and quantitatively defines the differences in calibration resulting from the use of different reference materials.
IgGSc antibodies in the serum specimens and reference materials were measured according to the manufacturers' instructions using commercially available IgGSc assays or components.
Data from four independent sites showed that in spite of the different commercial suppliers of IgGSc assays calibrating to different reference materials, ERM-DA470k and WHO67 /97, the resulting calibrations were comparable for IgG1 and IgG2. However, for IgG3 and IgG4 the calibrations were significantly different. The use of assay specific normal ranges should compensate for these calibration differences, however, the two manufacturers' assays can give differing clinical classifications. The agreement between the different manufacturers' IgGSc assays was between 85.1% and 95.8% for all IgGSc assays, the discordance of sample classification for IgG1 and IgG2 assays was approximately 12% and 15% respectively, whilst that for IgG3 and IgG4 was 4% and 13% respectively.
We discuss the similarities and differences between assays that utilise the different reference materials.
准确测量 IgG 亚类（IgGSc）水平对于辅助诊断原发性免疫缺陷等疾病状态至关重要。然而，目前尚无针对这些分析物的比浊法和散射比浊法的单一标准化方法，因此已经使用了两种参考物质。我们扩展了之前的报告，并提供了来自多地点分析的数据，该分析既确定了又定量定义了由于使用不同的参考物质而导致的校准差异。
根据制造商的说明，使用市售的 IgGSc 测定法或成分，测量血清标本和参考材料中的 IgGSc 抗体。
来自四个独立站点的数据表明，尽管 IgGSc 测定法的商业供应商不同，校准所用的参考物质也不同，即 ERM-DA470k 和 WHO67/97，但 IgG1 和 IgG2 的校准结果仍可比较。但是，对于 IgG3 和 IgG4，校准结果则有明显差异。尽管使用了特定于测定法的正常范围，但这些校准差异可以得到补偿，但是两个制造商的测定法可以给出不同的临床分类。对于所有 IgGSc 测定法，不同制造商的 IgGSc 测定法之间的一致性在 85.1%至 95.8%之间，对于 IgG1 和 IgG2 测定法，样品分类的不一致性约为 12%和 15%，而对于 IgG3 和 IgG4 则分别为 4%和 13%。
我们讨论了使用不同参考物质的测定法之间的相似点和差异。
