Carley S, Dosman S, Jones S R, Harrison M
Manchester Royal Infirmary, Manchester M13 9WL, UK.
Emerg Med J. 2005 Mar;22(3):180-1. doi: 10.1136/emj.2003.011148.
To produce an easily understood and accessible tool for use by researchers in diagnostic studies. Diagnostic studies should have sample size calculations performed, but in practice, they are performed infrequently. This may be due to a reluctance on the part of researchers to use mathematical formulae.
Using a spreadsheet, we derived nomograms for calculating the number of patients required to determine the precision of a test's sensitivity or specificity.
The nomograms could be easily used to determine the sensitivity and specificity of a test.
In addition to being easy to use, the nomogram allows deduction of a missing parameter (number of patients, confidence intervals, prevalence, or sensitivity/specificity) if the other three are known. The nomogram can also be used retrospectively by the reader of published research as a rough estimating tool for sample size calculations.
为诊断研究的研究人员制作一个易于理解和使用的工具。诊断研究应该进行样本量计算，但在实际中，这种计算很少进行。这可能是由于研究人员不愿使用数学公式。
我们使用电子表格得出了列线图，用于计算确定测试灵敏度或特异性的精度所需的患者数量。
列线图可轻松用于确定测试的灵敏度和特异性。
除了易于使用外，如果已知其他三个参数（患者数量、置信区间、患病率或灵敏度/特异性），列线图还可以推导缺失的参数。已发表研究的读者也可以将列线图作为样本量计算的粗略估计工具进行回顾性使用。
