Harris E K
Clin Chem. 1975 Sep;21(10):1457-64.
The conventional population-based normal range has recently been shown to be a generally defective reference criterion for assessing individual laboratory test results. Applying a previously derived formula to published data, we find that the use of age-, sex-specific normal ranges may fail to produce a substantial improvement in sensitivity over nonspecific ranges, even when age-sex differences in mean values are statistically significant. This occurs when the difference in means is not accompanied by a sufficient reduction in the variation among individuals within a given class. Turning therefore to comparison of an individual's current measurement with his own previous value(s), I suggest a simple statistical model that leads to sequential testing of each new observation against an exponentially weighted moving average of previous results. Estimates of biological and analytical components of variance are required. The ability of this method to detect trends in very short series is explored with the aid of computer-simulated laboratory data. A sample of these data is also used to illustrate the application of these estimation and testing procedures by means of a graph.
最近研究表明，传统的基于人群的正常范围通常是评估个体实验室检测结果的有缺陷的参考标准。将先前推导的公式应用于已发表的数据，我们发现，即使均值的年龄 - 性别差异具有统计学意义，使用年龄和性别特异性正常范围在敏感性方面可能不会比非特异性范围有实质性改善。当均值差异没有伴随着给定类别内个体变异的充分减少时，就会出现这种情况。因此，转向将个体当前测量值与其自身先前值进行比较，我提出了一个简单的统计模型，该模型导致针对先前结果的指数加权移动平均值对每个新观察值进行序贯检验。需要对方差的生物学和分析成分进行估计。借助计算机模拟的实验室数据，探讨了该方法在极短序列中检测趋势的能力。这些数据的一个样本还用于通过图表说明这些估计和检验程序的应用。
