Details

These measures of the clinical accuracy of a diagnostic test applied to a diseased and a nondiseased population can be calculated as functions of the sensitivity and the specificity of the test. Sensitivity is the fraction of the diseased population with a positive test result, while specificity is the fraction of the nondiseased population with a negative test result. If we denote by the sensitivity, the specificity and the prevalence, we have:

,

,

,

,

.

Given a diseased and a nondiseased population, the specificity can be defined as a function of sensitivity; therefore, we can generate the parametric plots of any pair of the diagnostic accuracy measures.

To the best of our knowledge, with the exception of the pair PPV and NPV [1, 2], the relation of any other pair of the given diagnostic accuracy measures has not been discussed in the literature.

In the thumbnail, the population data describes a bimodal distribution of serum glucose measurements in nondiabetic and diabetic populations [3].

This Demonstration is an extended version of another Demonstration [2], first published in 2015, and is appropriate as an educational tool for medical students and as an exploratory research tool in diagnostic accuracy studies.

References

[1] S.-Y. Shiu and C. Gatsonis, "The Predictive Receiver Operating Characteristic Curve for the Joint Assessment of the Positive and Negative Predictive Values," Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, 366(1874), 2008 pp. 2313–2333. doi:10.1098/rsta.2008.0043.

[2] T. Chatzimichail. "Correlation of Positive and Negative Predictive Values of Diagnostic Tests" from the Wolfram Demonstrations Project—A Wolfram Web Resource. demonstrations.wolfram.com/CorrelationOfPositiveAndNegativePredictiveValuesOfDiagnostic.

[3] 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. doi:10.2337/diacare.25.12.2212.