WBR0418
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| Author | [[PageAuthor::Yazan Daaboul, M.D. (Reviewed by Alison Leibowitz)]] |
|---|---|
| Exam Type | ExamType::USMLE Step 1 |
| Main Category | MainCategory::Biostatistics/Epidemiology |
| Sub Category | SubCategory::Vascular |
| Prompt | [[Prompt::The following table displays the results of a study investigating a new test for diagnosing aortic stiffness. What are the approximate sensitivity and specificity of the new test?
|
| Answer A | [[AnswerA::Sensitivity = 83%
Specificity = 67%]] |
| Answer A Explanation | [[AnswerAExp::Sensitivity (%) = TP/ (TP+FN) x 100 = 83%
Specificity (%) = TN/ (TN + FP) x 100 = 67%]] |
| Answer B | [[AnswerB::Sensitivity = 83%
Specificity = 80%]] |
| Answer B Explanation | AnswerBExp::Sensitivity is correct. However, 80% represents the negative predictive value (NPV) of the test. NPV is calculated using the following equation: NPV = TN/ (TN+FN) |
| Answer C | [[AnswerC::Sensitivity = 71%
Specificity = 80%]] |
| Answer C Explanation | [[AnswerCExp::71% represents the positive predictive value (PPV) of the test. PPV is calculated using the following equation: PPV = TP/ (TP+FP). 80% represents the negative predictive value (NPV) of the test. NPV is calculated using the following equation: NPV = TN/ (TN+FN)]] |
| Answer D | [[AnswerD::Sensitivity = 80%
Specificity = 71%]] |
| Answer D Explanation | [[AnswerDExp::71% represents the positive predictive value (PPV) of the test. PPV is calculated using the following equation: PPV = TP/ (TP+FP). 80% represents the negative predictive value (NPV) of the test. NPV is calculated using the following equation: NPV = TN/ (TN+FN)]] |
| Answer E | [[AnswerE::Sensitivity = 71%
Specificity = 67%]] |
| Answer E Explanation | AnswerEExp::71% represents the positive predictive value (PPV) of the test. PPV is calculated using the following equation: PPV = TP/ (TP+FP). On the other hand, specificity is correct. |
| Right Answer | RightAnswer::A |
| Explanation | [[Explanation::Sensitivity (%) = TP/ (TP+FN) x 100 = 100/(100+20) x 100 = (100/120) x 100= 83%
Specificity (%) = TN/ (TN + FP) x 100 = 80/(80+40) x 100 = (80/120) x 100 = 67%
|
| Approved | Approved::Yes |
| Keyword | WBRKeyword::Specificity, WBRKeyword::Sensitivity, WBRKeyword::Calculation, WBRKeyword::Equation, WBRKeyword::Aortic stiffness |
| Linked Question | Linked:: |
| Order in Linked Questions | LinkedOrder:: |
