Diagnosis I Dr. Brent E. Faught, Ph.D. Assistant Professor Faculty of Applied Health Sciences Brock University St.Catharines, ON, Canada

Guidelines for Diagnostic Literature Is this test potentially relevant to my practice? Is this test potentially relevant to my practice? Has the test been compared with a true gold standard? Has the test been compared with a true gold standard? Did this validation study include an appropriate spectrum of subjects? Did this validation study include an appropriate spectrum of subjects?

Guidelines for Diagnostic Literature Has work-up bias been avoided? Has work-up bias been avoided? Has expectation bias been avoided? Has expectation bias been avoided? Was the test shown to be reproducible? Was the test shown to be reproducible? What are the features of the test as derived from this validation study? What are the features of the test as derived from this validation study?

Guidelines for Diagnostic Literature Were confidence intervals given? Were confidence intervals given? Has a sensible "normal range" been derived? Has a sensible "normal range" been derived? Has this test been placed in the context of other potential tests in the diagnostic sequence? Has this test been placed in the context of other potential tests in the diagnostic sequence?

Conditional Probabilities (T + ) (T - ) (D + ) TruePositive (D - ) FalseNegativeTrueNegative FalsePositive Gold Standard ClinicalTest

Interpretation of Diagnostic Data (T + ) (T - ) (D + ) A (D - ) CD B P ( T +  D + ) (A + C) OR__A__

Interpretation of Diagnostic Data (T + ) (T - ) (D + ) A (D - ) CD B P ( T -  D - ) (B + D) OR__D__

Interpretation of Diagnostic Data (T + ) (T - ) (D + ) A (D - ) CD B P ( T -  D + ) (A + C) OR__C__

Interpretation of Diagnostic Data (T + ) (T - ) (D + ) A (D - ) CD B P ( T +  D - ) (B + D) OR__B__

Interpretation of Diagnostic Data (T + ) (T - ) (D + ) A (D - ) CD B P ( D + )  OR (A + C)