Basic Concepts in Diagnostic Testing PDF

4/16/2024 Basic Concepts in Diagnostic Testing The Science Behind Your Peace of Mind 1...

4/16/2024 Basic Concepts in Diagnostic Testing The Science Behind Your Peace of Mind 1 False Positive Rate A diagnostic test Sensitivity seeks to identify "Accuracy" How do we a disease characterize condition, in performance of a diagnostic test? order to enable its clinical PPV management Specificity The Science Behind Your Peace of Mind 2 1  4/16/2024 MP: “I am sensing cancer on this margin; I will call it positive.” Sensitivity: probability the diagnostic test will identify disease when disease is present i.e. in a patient with a positive margin, what is the probability that MarginProbe will call it positive? 3 True False Positive Negative cancer cancer removed not removed Sensitivity: probability the diagnostic test will identify disease when disease is present i.e. In a patient with a positive margin, what is the probability that MarginProbe will call it positive? 4 2  4/16/2024 MP: “I found the positive margin for you!” Surgeon: “Thanks, but could you be a little more specific??” Specificity: probability the diagnostic test will identify healthy tissue when healthy tissue is present i.e. in a patient with a clear margin, what is the probability that MarginProbe will call it negative? 5 False True Positive Negative healthy healthy tissue tissue not removed removed Specificity: probability the diagnostic test will identify healthy tissue when healthy tissue is present i.e. in a patient with a clear margin, what is the probability that MarginProbe will call it negative? 6 3  4/16/2024 Pathology + (Cancer) - (Normal) MarginProbe + - The Science Behind Your Peace of Mind 7 Pathology + (Cancer) - (Normal) MarginProbe + True Positive (cancer removed) - The Science Behind Your Peace of Mind 8 4  4/16/2024 Pathology + (Cancer) - (Normal) MarginProbe + True Positive (cancer removed) - False Negative (cancer not removed) The Science Behind Your Peace of Mind 9 Pathology + (Cancer) - (Normal) MarginProbe + True Positive (cancer removed) False Positive (normal tissue removed) - False Negative (cancer not removed) The Science Behind Your Peace of Mind 10 5  4/16/2024 Pathology + (Cancer) - (Normal) MarginProbe + True Positive (cancer removed) False Positive (normal tissue removed) - False Negative (cancer not removed) True Negative (normal tissue not removed) The Science Behind Your Peace of Mind 11 Pathology + (Cancer) - (Normal) MarginProbe + True Positive (cancer removed) False Positive (normal tissue removed) - False Negative (cancer not removed) True Negative (normal tissue not removed) Sensitivity: Specificity: % cancer correctly identified % healthy tissue correctly identified TP/(TP+FN) TN/(TN+FP) The Science Behind Your Peace of Mind 12 6  4/16/2024 Pathology + (Cancer) - (Normal) MarginProbe + True Positive (cancer removed) False Positive (normal tissue removed) - False Negative (cancer not removed) True Negative (normal tissue not removed) Sensitivity: Specificity: % cancer correctly identified % healthy tissue correctly identified TP/(TP+FN) TN/(TN+FP) # healthy found of all healthy False Negative Rate: False Positive Rate: % cancer missed % healthy tissue called malignant FN/(TP+FN) FP/(TN+FP) False Negative Rate= 1-Sensitivity False Positive Rate= 1-Specificity The Science Behind Your Peace of Mind 13 Pathology + (Cancer) - (Normal) MarginProbe PPV + True Positive (cancer removed) False Positive (normal tissue removed) TP/(TP+FP) - True Negative NPV False Negative (cancer not removed) (normal tissue not removed) TN/(TN+FN) Sensitivity: Specificity: TP/(TP+FN) TN/(TN+FP) False Negative Rate: False Positive Rate: FN/(TP+FN) FP/(TN+FP) The Science Behind Your Peace of Mind 14 7  4/16/2024 MarginProbe: TP/(TP+FN) Sensitivity False Negative Rate Pathology: TN/(TN+FP) Specificity False Positive Rate Pathology + - MarginProbe + What is the (likely) clinical outcome? - The Science Behind Your Peace of Mind 15 MarginProbe: TP/(TP+FN) Sensitivity False Negative Rate Pathology: TN/(TN+FP) Specificity False Positive Rate Pathology + - MarginProbe + 2 2 What is the (likely) clinical outcome? - 0 2 The Science Behind Your Peace of Mind 16 8  4/16/2024 MarginProbe: TP/(TP+FN) Sensitivity 2/2 = 100% False Negative Rate 0/2 = 0% Pathology: TN/(TN+FP) Specificity 2/4 = 50% False Positive Rate 2/2 = 50% Pathology + - MarginProbe + 2 2 What is the (likely) clinical outcome? - 0 2 The Science Behind Your Peace of Mind 17 MarginProbe: TP/(TP+FN) Sensitivity False Negative Rate Pathology: TN/(TN+FP) Specificity False Positive Rate Pathology + - MarginProbe + What is the (likely) clinical outcome? - The Science Behind Your Peace of Mind 18 9  4/16/2024 MarginProbe: TP/(TP+FN) Sensitivity False Negative Rate Pathology: TN/(TN+FP) Specificity False Positive Rate Pathology + - MarginProbe + 1 0 What is the (likely) clinical outcome? - 1 4 The Science Behind Your Peace of Mind 19 MarginProbe: TP/(TP+FN) Sensitivity 1/2 = 50% False Negative Rate 1/2 = 50% Pathology: TN/(TN+FP) Specificity 4/4 = 100% False Positive Rate 0/4 = 0% Pathology + - MarginProbe + 1 0 What is the (likely) clinical outcome? - 1 4 The Science Behind Your Peace of Mind 20 10  4/16/2024 sensitivity Which is more true positive specificity important? false negative true negative false positive The Science Behind Your Peace of Mind 21 how accurate is it? There are how often does it correctly identify a positive margin? Sensitivity multiple what is the sensitivity? what is your false negative rate? ways you how often does it miss cancer? will hear how accurate is it? what is your false positive rate? the same Specificity what is the specificity? question how often does it direct to take tissue and then pathology report shows we didn’t have to take it? The Science Behind Your Peace of Mind 22 11  4/16/2024 The Science Behind Your Peace of Mind 23 12  4/16/2024 Evaluation of Lumpectomy Margins in Surgical Pathology: Pathology 101 1 Pathology is the study and diagnosis of disease through the examination of surgically removed organs, tissues, bodily fluids, or autopsy primary focus examining tissues with naked eye or under microscope for definitive diagnosis of disease Surgical Pathology involves macroscopic (gross) and microscopic (histologic) tissue analysis studies and diagnoses disease on cellular level Cytopathology generally used on samples of free cells or tissue fragments that spontaneously exfoliate or are removed from tissues by abrasion or fine needle aspiration studies and diagnoses disease through examination of molecules within organs, tissues or bodily fluids Molecular Pathology Identifies mutations or alterations in genetic code of patient to classify disease and choose appropriate treatment The Science Behind Your Peace of Mind 2 1  4/16/2024 Successful lumpectomy is clear margin predicated on achieving a tumor pathologically clear margin The Science Behind Your Peace of Mind 3 Pathologic processing of a breast specimen Orientation Specimen Inking Gross Assessment Paraffin Embedding Cassettes and Slicing Microscope 4 2  4/16/2024 To assess MarginProbe performance, we must compare device results to the Gold Standard Accepted as true Final histopathology is description of tissue and the Gold Standard margin “Gold Standard” does ink seeping