Fraser C G, Petersen P H
Department of Biochemical Medicine, Ninewells Hospital and Medical School, Dundee, Scotland, UK.
Clin Chem. 1993 Jul;39(7):1447-53; discussion 1453-5.
Many strategies to define desirable standards for laboratory tests to fulfill medical needs have been proposed over the last three decades. Traditional approaches are based on reference (normal) values, opinions of clinicians, the state of the art, views of experts, data on biological variation, and assessment of the effect of error on clinical use. All these approaches have advantages and disadvantages, but the consensus of experts reached over a decade ago that imprecision desirably be less than one-half of the within-subject biological variation still seems to provide the best set of generally applicable performance standards. Desirable bias is less than one-quarter of the group (within-subject plus between-subject) biological variation. Recent proposals are either restatements of traditional recommendations, further empirical suggestions, or models based on assessment of clinical needs, and have not been widely accepted. Both old and new studies on clinical opinions, sought by using structured questionnaires containing clinical vignettes designed to seek views on the magnitude of significant change, are flawed in design, execution, and data analysis. Until clinicians are more aware of test-result variability and clinical chemists gain quantitative knowledge on the interpretation of test results, it will be difficult to set desirable standards that fulfill actual medical needs, except in a few well-defined screening situations.
在过去三十年里，人们提出了许多为满足医学需求而界定实验室检测理想标准的策略。传统方法基于参考（正常）值、临床医生的意见、现有技术水平、专家观点、生物变异数据以及误差对临床应用影响的评估。所有这些方法都各有优缺点，但十多年前专家们达成的共识是，理想情况下不精密度应小于个体内生物变异的一半，这似乎仍然提供了一套最佳的普遍适用性能标准。理想偏差应小于群体（个体内加个体间）生物变异的四分之一。最近的提议要么是对传统建议的重新表述、进一步的经验性建议，要么是基于临床需求评估的模型，尚未被广泛接受。通过使用包含临床病例 vignettes 以寻求对显著变化幅度看法的结构化问卷来获取临床意见的新旧研究，在设计、实施和数据分析方面都存在缺陷。除非临床医生更加了解检测结果的变异性，临床化学家获得关于检测结果解读的定量知识，否则很难制定出满足实际医学需求的理想标准，少数明确界定的筛查情况除外。
