Determining Diagnostic Test Quality

1. Sensitivity

1.1. It is the true positive rate

1.2. Sensitivity of a test is the percentage of all patients with disease present who have a positive test

1.3. sensitivity= TP/ (TP+FN)

2. Specificity

2.1. It is the the true negative rate

2.2. Specificity of a test is the percentage of all patients without disease who have a negative test.

2.3. specificity=TN/(TN+FP)

3. Positive predictive value

3.1. the percent of all positive tests that are true positives

3.2. PPV=TP/(TP+TN)

4. Negative predictive value

4.1. the percent of all negative tests that are true negative

4.2. NPV=TN/(TN+FN)

5. The diagnostic value of a procedure is defined by its sensitivity, specificity, predictive value and efficiency.

6. Useful Links

6.1. Clinical tests sensitivity and specificity

6.2. Sensitivity, Specificity and Predictive Values

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