摘要探讨设计以验证灵敏度和特异度为目的 的诊断试验时,不同样本量计算方法间的区别.通过直观的样本量公式与计算结果比较,分析不同样本量计算方法间的差异,进一步通过Monte Carlo随机模拟方法,验证所得结果的正确性.抽样调查法计算所需的样本量明显低于单组目标值法,随机模拟显示,在相同的参数设置下,单组目标值法给出的样本量能够提供更高的研究把握度.两种样本量设计方法的适用条件不同,存在本质区别,研究者必须根据研究目的 设置相应参数,如果在以检验某种诊断方法的诊断能力是否不低于某个临床认可的标准时,按照单组目标值法设计的样本量,才能提供足够的检验把握度,证明新诊断方法的有效性.

abstractsTo discuss the calculation methods under different sample size, used for diagnostic trials. The purpose of the diagnostic trial was to demonstrate the sensitivity and specificity of the new method. Equations and results were directly compared. Monte Carlo random simulation was used to validate the results. Sample size obtained from the sampling method was always smaller than from the target value method. Results from simulation showed that the target value method could offer more and larger power. The two sample size determination method showed essential differences of the results, suggesting that the investigator should choose appropriate method in accordance with the study design. If the hypothesis of study was to demonstrate the new diagnostic method which could meet the clinical requirements, only if the target value method provides enough statistical power.