Uncertainty of Measurement and Diagnostic Accuracy Measures
In addition to the receiver operating characteristic (ROC) curves, various measures are used in the evaluation of the clinical accuracy of a diagnostic test applied to a diseased or a nondiseased population. They can be calculated versus the sensitivity or the specificity of the test. Sensitivity is the fraction of the diseased population with a positive test, while specificity is the fraction of the nondiseased population with a negative test. In addition, if we denote by the sensitivity, the specificity, and the prevalence, we have: , , , , . This Demonstration could be useful in evaluating the maximum medically permissible uncertainty of measurement of a diagnostic test. For example, in the thumbnail and the snapshots the populations data describes a bimodal distribution of serum glucose measurements with a nondiabetic and a diabetic population (Lim et al. 2002). The first test has a state-of-the-art performance, while the second test has a greater uncertainty. Reference: T. O. Lim, R. Bakri, Z. Morad, and M. A. Hamid, "Bimodality in Blood Glucose Distribution: Is It Universal?," Diabetes Care, 25(12), 2002 pp. 2212–2217.