Screening, Diagnosis, Monitoring
Educational orientation
Source-checked: 2026-06-05. This page is not a screening or care recommendation.
Core Idea
Screening, diagnosis, and monitoring answer different questions. Screening looks for signs of disease in people who do not have a known diagnosis. Diagnosis asks whether a specific person has a specific disease. Monitoring follows known disease, risk, response, or recurrence over time.
Confusing these tasks leads to bad reasoning. A useful screening test must balance benefit, false positives, false negatives, overdiagnosis, access, and population risk. A diagnostic test is interpreted in a clinical context.
Essential Vocabulary
- Sensitivity: ability to catch positives.
- Specificity: ability to avoid false positives.
- False positive: test suggests disease when it is absent.
- Overdiagnosis: detecting disease that would not have caused harm.
What This Does Not Mean
More testing is not automatically better. Test value depends on the question and population.
Builder/Data Lens
Model thresholds change false positives and false negatives. Report the intended use before reporting performance.
Go Deeper
References
- National Cancer Institute. Cancer Screening
- National Cancer Institute. Tests and Procedures Used to Diagnose Cancer