WBR0793
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| Author | [[PageAuthor::Serge Korjian M.D. (Reviewed by Serge Korjian)]] |
|---|---|
| Exam Type | ExamType::USMLE Step 1 |
| Main Category | MainCategory::Biostatistics/Epidemiology |
| Sub Category | SubCategory::Reproductive |
| Prompt | [[Prompt::A new urine pregnancy test is being evaluated before marketing. A trial is conducted to compare the results of this new test to a combination of imaging and blood human chorionic gonadotropin (HCG) levels to validate the pregnancy. A table comparing the results of the study is shown below. What is the probability that a woman is truly pregnant if her urine pregnancy test is positive?
|
| Answer A | AnswerA::85.71% |
| Answer A Explanation | AnswerAExp::This refers to the sensitivity. |
| Answer B | AnswerB::75% |
| Answer B Explanation | AnswerBExp::This refers to the positive predictive value. |
| Answer C | AnswerC::89.28% |
| Answer C Explanation | AnswerCExp::This refers to the NPV. |
| Answer D | AnswerD::80.64% |
| Answer D Explanation | AnswerDExp::This refers to the specificity. |
| Answer E | AnswerE::62% |
| Answer E Explanation | AnswerEExp::This does not refer to any particular value. |
| Right Answer | RightAnswer::B |
| Explanation | [[Explanation::The positive predictive value is the probability that a person really has a condition if their test result is positive. The calculation is shown below.
|
| Approved | Approved::Yes |
| Keyword | WBRKeyword::Positive predictive value |
| Linked Question | Linked:: |
| Order in Linked Questions | LinkedOrder:: |
