Newill C A, Khoury M J, Chase G A
J Occup Med. 1986 Oct;28(10):1108-11. doi: 10.1097/00043764-198610000-00036.
Using several examples of genetic marker and disease associations in the workplace, the authors have applied formulas to estimate the sensitivity, specificity, and positive predictive value (PPV) of screening for these markers. Sensitivity, specificity, and PPV are affected independently by characteristics of the population being screened, ie, the genetic marker frequency, the disease frequency, and the magnitude of the relative risk (R). For a given disease frequency, when the genetic marker is less frequent than the disease, PPV increases with relative risk, although sensitivity remains low. When the genetic marker is more frequent than the disease, PPV remains low while sensitivity increases with R. When marker and disease frequencies are equal, PPV and sensitivity are equal and increase with R. However, when the disease frequency is very low, R must approach 100 before PPV or sensitivity approaches 50%. These relationships may be used effectively in the decision whether to implement a screening program in the workplace.
通过工作场所中遗传标记与疾病关联的几个例子，作者应用公式来估计针对这些标记进行筛查的敏感性、特异性和阳性预测值（PPV）。敏感性、特异性和PPV独立地受到被筛查人群特征的影响，即遗传标记频率、疾病频率和相对风险（R）的大小。对于给定的疾病频率，当遗传标记比疾病的频率低时，尽管敏感性仍然较低，但PPV会随着相对风险的增加而增加。当遗传标记比疾病的频率高时，PPV仍然较低，而敏感性则随着R的增加而增加。当标记频率和疾病频率相等时，PPV和敏感性相等且随着R的增加而增加。然而，当疾病频率非常低时，在PPV或敏感性接近50%之前，R必须接近100。这些关系可有效地用于决定是否在工作场所实施筛查计划。
