WBR0379
| Author | PageAuthor::Mahmoud Sakr M.D. |
|---|---|
| Exam Type | ExamType::USMLE Step 1 |
| Main Category | MainCategory::Biostatistics/ Epidemiology |
| Sub Category | SubCategory::Gastrointestinal |
| Prompt | [[Prompt::Researchers are performing a study to evaluate a new lab test that screens patients for ulcerative colitis. Each patient with ulcerative colitis taking the test either has or does not have the disease. The test outcome can be positive (predicting that the person has the disease) or negative (predicting that the person does not have the disease. The test's ability to identify positive results in true ulcerative colitis patients is known as:]] |
| Answer A | AnswerA::Sensitivity |
| Answer A Explanation | [[AnswerAExp::Sensitivity relates to the test's ability to identify positive results. The sensitivity of a test is the proportion of people that are known to have the disease who test positive for it. Specificity relates to the test's ability to identify negative results. It is the proportion of patients that are known not to have the disease who will test negative for it. The positive predictive value, or precision rate is the proportion of positive test results that are true positives (such as correct diagnoses). Negative predictive value is the proportion of subjects with a negative test result who are correctly disease-free.]] |
| Answer B | AnswerB::Specificity |
| Answer B Explanation | AnswerBExp::Specificity relates to the test's ability to identify negative results. It is the proportion of patients that are known not to have the disease who will test negative for it. |
| Answer C | AnswerC::Positive predictive value |
| Answer C Explanation | AnswerCExp::The positive predictive value, or precision rate is the proportion of positive test results that are true positives (such as correct diagnoses). |
| Answer D | AnswerD::Negative predictive value |
| Answer D Explanation | AnswerDExp::Negative predictive value is the proportion of subjects with a negative test result who are correctly disease-free. |
| Answer E | AnswerE::Likelihood ratio |
| Answer E Explanation | [[AnswerEExp::Likelihood ratios are used for assessing the value of performing a diagnostic test. A likelihood ratio of greater than 1 indicates the test result is associated with the disease. A likelihood ratio less than 1 indicates that the result is associated with absence of the disease.]] |
| Right Answer | RightAnswer::A |
| Explanation | [[Explanation:: Educational Objective: |
| Approved | Approved::Yes |
| Keyword | |
| Linked Question | Linked:: |
| Order in Linked Questions | LinkedOrder:: |