Medizinische Hochschule Hannover, Institute of Clinical Chemistry, Carl-Neuberg-Str. 1, 30625 Hannover, Germany.
Roche Diagnostics, Nonnenwald 2, 82377 Penzberg, Germany.
Clin Chim Acta. 2018 Jun;481:115-120. doi: 10.1016/j.cca.2018.02.037. Epub 2018 Mar 1.
For the determination of total bilirubin in serum the candidate reference method developed by Doumas et al. has international recognition. The primary standard SRM 916a (NIST) was recommended for use as the primary reference material for calibration. Nowadays, no primary standard is anymore commercially available. Further, a description of uncertainty components was missing.
Two reference laboratories have re-investigated the candidate reference measurement procedure. Beside minor modifications, mainly the use of a molar absorption coefficient instead of calibration by use of bilirubin standard solutions has facilitated the operating, and improved the analytical performance. All relevant sources of measurement uncertainty were investigated.
A measurement range of 5-525 μmol/L and a CV of 0.5% to 1.4% (long term imprecision) were determined. Excellent agreement was obtained comparing to Doumas procedure (r = 0.9999) and during a two laboratory comparison participating at IFCC RELA ring trials (mean deviation: 0.6%). The combined expanded measurement uncertainty (probability 95%) for bilirubin concentrations >30 μmol/L was estimated as 2.2%.
A reference system for total bilirubin based on the described reference procedure shall enable metrological traceability and optimized standardization of the values obtained in clinical routine laboratories.
为了测定血清总胆红素，道马等人开发的候选参考方法已得到国际认可。初级标准物质 SRM 916a（NIST）被推荐用作校准的主要参考物质。如今，已不再有商业用途的主要标准物质。此外，还缺少对不确定度分量的描述。
两个参考实验室重新研究了候选参考测量程序。除了进行一些微小的修改，主要是使用摩尔吸光系数而不是使用胆红素标准溶液进行校准，这使得操作更加简便，并提高了分析性能。研究了所有相关的测量不确定度来源。
确定了 5-525 μmol/L 的测量范围和 0.5%至1.4%的 CV（长期不精密度）。与道马方法（r=0.9999）相比，以及在参与 IFCC RELA 环试验的两个实验室比较中，都获得了极好的一致性（平均偏差：0.6%）。对于胆红素浓度>30 μmol/L，组合扩展测量不确定度（概率 95%）估计为 2.2%。
基于所描述的参考程序的总胆红素参考系统将能够实现计量溯源，并优化临床常规实验室获得的值的标准化。
