Effects of Prevalence on Diagnostic Tests
2 X 2 Table: Sensitivity and Specificity
| Breast Cancer |
Total |
||
| Positive |
Negative |
||
| Physical Examination | |||
| Positive (lump) |
80 |
10 | 90 |
| Negative (no lump) | 20 | 90 | 110 |
| Total | 100 | 100 | 200 |
Reflection
Calculate the sensitivity of the physical exam of the breast in the diagnosis of breast cancer.
Reflection
Calculate the specificity of the physical exam of the breast for breast cancer.
Reflection
What is the positive predictive value of a breast lump?
Reflection
What is the negative predictive value?