Sensitivity, Specificity, and Predictive Values in the 'Sensitivity and Specificity of Clinical Diagnostics'

Abstract

To the Editor.— There was a confusing explanation of sensitivity and specificity in the article by Anderson et al 1 in the March 17 issue. Assuming proper use of the terms true positives, true negatives, false positives , and false negatives , sensitivity and specificity are defined correctly in the Methods section and in the footnote to Table 1. However, it appears that the correct positions of false negatives and false positives were switched in Table 1 (Table). This distinction is important, because if the data for all subsequent tables were analyzed as described in the published Table 1, then what is reported as the sensitivity is actually the predictive value of a positive, and the reported clinical accuracy of a positive diagnosis is actually the sensitivity. A similar switch would also have occurred with the specificity and the clinical accuracy of a negative diagnosis.