There are 6 levels of diagnostic test quality that we should consider: (Fryback 1991)
- Technical quality of the test information
- Diagnostic accuracy
- Change in the physician’s diagnostic thinking
- Change in management plans
- Change in patient outcomes
- Societal costs and benefits
We frequently assume that if a test has great diagnostic accuracy that it should be used in practice, but a glance at this list reminds us that it is really patient outcomes that we should care about. Tests with increased sensitivity may appear better, but in fact might be detecting a new spectrum of disease. Therefore, one cannot simply extrapolate improved detection with better patient outcomes. (Lord 2006)
References
Fryback DG, Thornbury JR. The efficacy of diagnostic imaging. Medical decision making : an international journal of the Society for Medical Decision Making. ; 11(2):88-94. PMID: 1907710
Lord SJ, Irwig L, Simes RJ. When is measuring sensitivity and specificity sufficient to evaluate a diagnostic test, and when do we need randomized trials? Annals of internal medicine. 2006; 144(11):850-5. PMID: 16754927
Morgenstern, J. Evidence for Diagnostic Tests, First10EM, January 7, 2018. Available at:
https://doi.org/10.51684/FIRS.5586