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CMEUser, Bureaucrats, nocaptcha, Administrators
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Rim Halaby (talk | contribs)
CMEUser, Bureaucrats, nocaptcha, Administrators
27,346 edits
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Line 20: Line 20:
|MainCategory=Biostatistics/ Epidemiology
|MainCategory=Biostatistics/ Epidemiology
|SubCategory=Cardiology
|SubCategory=Cardiology
|Prompt=A new diagnostic test is being evaluated for the diagnosis of DVT. Patients presenting to a large central hospital with symptoms suggestive of DVT are evaluated using this new test in conjunction with the gold standard for diagnosis. Knowing that the gold standard has a sensitivity and specificity approaching 100% it is used to determine the true incidence of DVT. The table below shows the result of the initial data collection. Which of the following combinations are true regarding this diagnostic test?
|Prompt=A company is testing a new diagnostic tool for the detection of squamous cell carcinoma of the skin and comparing the results to biopsy specimens validated by professional dermatopathologists. The results are shown below. What is the probability that a person really doesn't have squamous cell carcinoma if his test result comes back negative?




[[Image:WBR0791.jpg|500px]]
[[Image:WBR0792.png|500px]]
|Explanation=[[Image:Biostat.png|600px]]
|Explanation=The negative predictive value is the probability that a person really doesn't have disease if a test result is negative. The calculation is shown below.
|AnswerA=Sensitivity: 93.75 / Specificity: 74.46
 
|AnswerAExp=This is the correct combination.
 
|AnswerB=Sensitivity: 74.46 / Specificity: 93.75
[[Image:Biostat.png|600px]]
|AnswerBExp=Incorrect
|AnswerA=82.75%
|AnswerC=Sensitivity: 71.42 / Specificity: 94.59
|AnswerAExp=This refers to the sensitivity.
|AnswerCExp=This refers to the positive predictive value and the negative predictive value respectively.
|AnswerB=80%
|AnswerD=Sensitivity: 94.59 / Specificity: 71.42
|AnswerBExp=This refers to the positive predictive value.
|AnswerDExp=Incorrect
|AnswerC=94.11%
|AnswerE=Cannot be calculated with the given data
|AnswerCExp=This refers to the NPV.
|AnswerEExp=All the values needed are available to calculate both the sensitivity and specificity.
|AnswerD=93.02%
|RightAnswer=A
|AnswerDExp=This refers to the specificity.
|WBRKeyword=Specificity, Sensitivity
|AnswerE=76.92%
|RightAnswer=C
|WBRKeyword=Negative predictive value
|Approved=No
|Approved=No
}}
}}

Revision as of 00:12, 31 October 2013
Author [[PageAuthor::Rim Halaby, M.D. [1]]]
Exam Type ExamType::USMLE Step 1
Main Category MainCategory::Biostatistics/ Epidemiology
Sub Category SubCategory::Cardiology
Prompt [[Prompt::A company is testing a new diagnostic tool for the detection of squamous cell carcinoma of the skin and comparing the results to biopsy specimens validated by professional dermatopathologists. The results are shown below. What is the probability that a person really doesn't have squamous cell carcinoma if his test result comes back negative?


File:WBR0792.png]]

Answer A AnswerA::82.75%
Answer A Explanation AnswerAExp::This refers to the sensitivity.
Answer B AnswerB::80%
Answer B Explanation AnswerBExp::This refers to the positive predictive value.
Answer C AnswerC::94.11%
Answer C Explanation AnswerCExp::This refers to the NPV.
Answer D AnswerD::93.02%
Answer D Explanation AnswerDExp::This refers to the specificity.
Answer E AnswerE::76.92%
Answer E Explanation AnswerEExp::
Right Answer RightAnswer::C
Explanation [[Explanation::The negative predictive value is the probability that a person really doesn't have disease if a test result is negative. The calculation is shown below.



Educational Objective:
References: ]]

Approved Approved::No
Keyword WBRKeyword::Negative predictive value
Linked Question Linked::
Order in Linked Questions LinkedOrder::
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