This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Microbiology
[{'content': 'All of the following methods are used for the diagnosis of HIV infection in a 2 month old child, \nSelect and explain. \nA. DNA-PCR., B. Viral culture., C. HIV ELISA, D. p24 antigen assay', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Anti-HIV antibody detection by ELISA or any other method is done only after 18 months of birth when all maternal\xa0antibodies would have disappeared.\nHIV diagnosis <18 months: (i) HIV DNA detection (best), (ii) p-24 antigen, (iii) HIV RNA detection, (iv) virus isolation', 'role': 'assistant'}]