Diagnostic tests (or diagnostic screening tests) are often used in clinical medical practice to estimate the likelihood that a person does or does not have a particular medical condition. The rationale is that, if the disease is identified early (before symptoms manifest), earlier treatment may lead to cure or improved survival or quality of life. Screening tests for diagnosis are usually laboratory or other tests that detect particular markers of a specific disease.

Calculations:
- Accuracy
- Sensitivity
- Specificity
- Positive Predictive Value
- Negative Predictive Value
- Positive Likelihood Ratio
- Negative Likelihood Ratio
- False Positive Likelihood Ratio
- False Negative Likelihood Ratio
- False Discovery Ratio
- False Omission Ratio
- Marker Ratio
- Information Ratio