biosensors Lecture 3- diagnostic accuracy

methods for determining diagnostic accuracy

• confusion matrix

• ROC curve

confusion matrix

• binary test or a specific cutoff value

• used to visualize and describe the performance of a test

Receiver Operating Characteristic (ROC) curve

plot with various cutoffs

application of a confusion matrix

helps determine if a device can be used for screening, diagnostics, or both

confusion matrix- sensitivity

• a highly sensitive test helps to rule out the condition (when the result is negative)

• Sn out → “Snout”

confusion matrix- Specificity

• a highly specific test helps to rule in the condition (when the result is positive)

• Sp in → “Spin”

a highly sensitive test is good for…

screeing

a highly specific test is good for…

diagnostics

how is the ROC curve created?

• scans different cutoff values and computes true positive and false positive rates

what does ROC curve say about accuracy?

• the closer the ROC curve is to the upper left corner, the higher the overall accuracy of the test

example of creating ROC curve

• steps for creating histogram and ROC curve