Sensitivity and Specificity
Predictive Values - PPV
Positive Predictive Value (PPV)
The positive predictive value (PPV) is the probability that the positive findings for the diagnostic test are correct. In this situation, the PPV is the probability that your positive identification of thyroid enlargement by physical exam is right. In order to calculate PPV, you will need to know the number of true positives detected by the test divided by all patients who had a positive test.
| Ultrasound (gold standard) | Total | ||
| Enlarged (+) | Not Enlarged (-) | ||
| Physical Examination | |||
| Enlarged (+) | 30 | 20 | 50 |
| Not Enlarged (-) | 10 | 40 | 50 |
| Total | 40 | 60 | 100 |
Multi-choiceCalculate the PPV for your diagnostic test. Which of the following is the correct PPV?
|
67%
| |
|
75%
| |
|
50%
| |
|
60%
|