Uncertainty of Measurement and Diagnostic Accuracy Measures

DETAILS

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 sens the sensitivity, spec the specificity, and pr the prevalence, we have: 
PPV=((sens×pr)/(sens×pr+(1-spec)(1-pr))), NPV=((spec(1-pr))/(spec(1-pr)+(1-sens)pr)), OR=((sens/(1-sens))/((1-spec)/spec)), LR+ =(sens/(1-spec)), LR- =((1-sens)/spec).
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.

THIS NOTEBOOK IS THE SOURCE CODE FROM

Aristides T. Hatjimihail

"Uncertainty of Measurement and Diagnostic Accuracy Measures"
 http://demonstrations.wolfram.com/UncertaintyOfMeasurementAndDiagnosticAccuracyMeasures/
 Wolfram Demonstrations Project
 Published: May 26, 2009

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