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  #1  
Old 04-29-2015
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Default Another tricky question in USMLE 2015

A 23 year old visits his physician for the first time after learning that he is HIV positive. He is concerned about developing AIDS. Which test is the most useful predictor for his developing AIDS?

A- HIV antibody test
B- HIV RT PCR
C- HIV p24 antigen
D- CD4 lymphocyte count
http://medical-usmle.com/?p=910

Last edited by sohag100; 04-30-2015 at 01:33 PM.
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Old 04-30-2015
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D) CD4 count.
if CD4 count goes below 200 it's considered AIDS defining illness. Leading to PCP, Crypto, MAC, etc.
A, B, C) is a yes or no to infection with HIV.

EDIT: WHAAAAAAA????? Link says I'm wrong, but CDC panel says its CD4 count, RT-RNA is real time RNA, meaning "Do you have HIV RNA present" = HIV +.

Last edited by Winterfell; 04-30-2015 at 04:52 AM.
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Old 04-30-2015
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Default That's why it is tricky

Your answer would be correct if the question asks to confirm the diagnosis of AIDS. But it is not, it asks about the possibility to convert to AIDS which is totally different. If CD4 is already down, then the patient already has AIDS. Quantitative RT PCR should make more sense to be the right answer. What do you think?
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Old 04-30-2015
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Quote:
Originally Posted by sohag100 View Post
Your answer would be correct if the question asks to confirm the diagnosis of AIDS. But it is not, it asks about the possibility to convert to AIDS which is totally different. If CD4 is already down, then the patient already has AIDS. Quantitative RT PCR should make more sense to be the right answer. What do you think?

I think Low CD4 is the first thing we check,... and then anything else after that.. I dont remember where I read this.. but i think CD4 would be the answer...
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Old 04-30-2015
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Default so what if the CD4 is low

I want to make it simple....what if I ask you about the possibility that a smoker can develop lung cancer.....do you think the answer would be if you find patches of cancer already on his lung...it is the same concept....if his CD4 is already low then he has AIDS....the question asks about the prognosis of HIV..it is completely different. Prognosis is bad if there is a huge number of viral load....Anyways, I am sure about the answer is B...but you are free to answer it the way you want....
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Old 04-30-2015
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This is a stupid question - it assumes that the patient has no dealings with a physician. In truth, the viral load would be tested on a routine basis to make certain that the patient is taking the medication and that a resistant strain has not appeared. Thus, the patient is asking a question beyond that - maybe - Do I have AIDS or will I get AIDS? - but it is not clear. Which explains why so many people select "D" and why this question was pulled from the exam!
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Old 04-30-2015
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Default I don't think so

I don't think it is a stupid question....I think it is the kind of questions that make the difference in scores....And by the way there is a lot of these questions in all steps of USMLE. The kind of questions that don't make sense on first impression but once you give it a second thought you will realize it is a very reasonable and simple questions...
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Old 04-30-2015
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Here is a possible fix:

A 23 year old visits his physician for the first time after learning that he is HIV positive. He is concerned about developing AIDS. Which test is the most useful predictor for his developing AIDS?
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Old 04-30-2015
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Default Yes it makes more sense...

I agree..you are right this way makes more sense...Thank you muellerd
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Old 04-30-2015
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Default HIV+

The criteria for AIDs is CD4 Count <350 cells/mm3 or when symptomatic at any level of CD4 counts. The risk of developing AIDs in HIV positive pt depends on retroviral RNA load, which can be detected by RT-PCR. so I will say it is HIV RT-PCR test which can detect estimated risk in this patient.
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Old 04-30-2015
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Another problem with this question is RT-PCR can mean either Real Time PCR and Reverse Transcriptase PCR. The reader might wrongly think that the question was asking if the virus was an RNA or DNA virus - Real Time PCR does not imply reverse transcriptase. I think they should have avoided RT PCR altogether and simply indicated viral load in the answer.
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Old 05-09-2015
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Default Stupid questions on the real test

Quote:
Originally Posted by muellerd View Post
Another problem with this question is RT-PCR can mean either Real Time PCR and Reverse Transcriptase PCR. The reader might wrongly think that the question was asking if the virus was an RNA or DNA virus - Real Time PCR does not imply reverse transcriptase. I think they should have avoided RT PCR altogether and simply indicated viral load in the answer.
Dear Dr Muellerd....you are looking for mistakes....I took all USMLE steps....How many stupid questions did I find during the real exam? I seriously found at least 30 or more stupid questions on every step.
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Old 05-19-2015
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I think correct answer is p 24 antigen early and acute marker
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Old 07-13-2015
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i think decreasing number of CD4 Lymphocytes is predicting the AIDS phase!but for a patient with a very recent HIV+ test, the CD4 will be normal.
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