1. Evidence Based Diagnosis Hesham Al-Inany, MD Cairo University

3. Increasing use of investigations: - Availability. - The urge to make use of new technology.

4. The evaluation of diagnostic techniques is less advanced than that of treatments. Unlike with drugs, there are generally no formal requirements for adoption of diagnostic tests in routine care. Diagnostic tests

5. The evaluation of diagnostic techniques is less advanced than that of treatments ( NO phase I, II, III, IV). New Diagnostic tests

9. Apply results to your patients Understand evidence Find the best evidence to answer questions clinical information needs Answerable questions EB Diagnosis

26. 2 X 2 Table d (true negative) c (false negative) b (false positive) a (true positive)

29. d c+d True negatives All screened negative Negative Predictive value a a+b True positives All screened positive Positive Predictive value d b+d True negatives All nondiseased Specificity a a+c True positives All diseased Sensitivity Formula Definition Measure

34. Interpreting likelihood ratios Large and often conclusive decrease in the likelihood of disease < 0.1 Moderate decrease in the likelihood of disease 0.1 - 0.2 Small decrease in the likelihood of disease 0.2 - 0.5 Minimal decrease in the likelihood of disease 0.5 - 1.0 No change in the likelihood of disease 1 Minimal increase in the likelihood of disease 1 - 2 Small increase in the likelihood of disease 2 - 5 Moderate increase in the likelihood of disease 5 - 10 Large and often conclusive increase in the likelihood of disease > 10 Interpretation LR

36. ROC curve is simply a graph of sensitivity vs (1-specificity)