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PERIPHERAL VASCULAR ULTRASOUND
calculating the specificity and sensitivity can permit the selection of the optimal threshold and allow the value of the diagnostic test to be assessed. Other closely related qualities of a test often quoted in the literature are the positive predictive value, the negative predictive value and the accuracy. The
Further reading
Bland M 1995 An introduction to medical statistics. Oxford University Press, Oxford
positive predictive value is the probability that a sub- ject who has a positive test (i.e., disease is detected) will be correctly classified. The negative predictive value is the probability that a subject who has a neg- ative test (i.e., no disease is detected) is correctly classified.