新鲜血液白细胞计数参考方法的测量不确定度评定

摘要

Objective To study the evaluation method and procedure on the uncertainty of leukocyte counts by reference method for fresh blood.Methods The reference method recommended by the International Committee for Standardization in Hematology(ICSH) was used for leukocyte counts.The components of uncertainty were validated. The International Organization for Standardization(ISO) Guide to the Expression of Uncertainty of Measurement (GUM), type A and type B methods were used to evaluate each component.Combined standard uncertainty and expanded uncertainty were calculated according to 95% confidence interval.Results The leukocyte counts from fresh blood had the average value of 6.71 ×109 /L.The combined standard uncertainty was 0.097 ×109 /L(95% confidence interval, coverage factor k =2), and the expanded uncertainty was 0.19 ×109 /L.Conclusions The main sources of uncertainty are from the overlapped calculation correction and pipetting volume.Therefore, there should be strictly control on pipetting volume in order to make lower uncertainty.The evaluation model of uncertainty is established, which can be applied to the leukocyte counts and standardization, providing effective methods for traceability.%目的：探讨新鲜血液白细胞计数参考方法测量不确定度的评定方法和程序。方法用国际临床血液学标准化委员会（ICSH）推荐的参考方法对新鲜血液样本进行白细胞计数；明确整个测定过程中测量不确定度分量来源，根据国标标准化组织（ISO）《测量不确定度表述指南》（GUM）文件中有关测量不确定度的评估方法，按 A、B 两类不确定度的计算方式对各分量分别进行评定，计算合成标准不确定度，最后取95％可信区间，计算出扩展不确定度。结果新鲜血液白细胞计数的均值为6．71×109／L；合成标准不确定度为0．097×109／L，取95％可信区间、包含因子 k ＝2，计算得扩展不确定度为0．19×109／L。结论新鲜血液白细胞计数参考方法的测量不确定度主要来源于重叠计数校正及加样体积。因此，对血液样本的加样稀释和测定应严加控制，确保测量结果具有较小的不确定度。同时建立了白细胞计数测量结果不确定度评估模型，可应用于白细胞计数项目的量值溯源和标准化，为常规检测系统向参考方法溯源提供有效途径。