Repeated USMLE Questions Step 1- 221

A 23 year old man visits his physician for routine examination. He has a history of HIV infection for 3 months and he is compliant with his medications. He is concerned about developing AIDS.

Which of the following is the most useful test to address his concern?

A-HIV antibody test

B-HIV RT PCR

C-HIV p24 antigen

D-CD4 lymphocyte count

Answer






The most recent and accurate test to determine the progress of HIV patient to develop AIDS is HIV RT PCR. Viral load of 750,000 increases significantly the chance to develop AIDS. HIV antibody test and HIV p24 antigen are important tests to diagnose HIV infection but they have no major rule in prognosis. CD4 lymphocyte count is the most common WRONG answer. It is used to check if the patient already developed AIDS and to evaluate the most possible complications. CD4 lymphocyte count is also important to determine prophylactic treatment for susceptible opportunistic infections.

The correct answer is B