This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General anatomy, Subject name: Anatomy
[{'content': 'Most common viral antigen used for diagnosis of HIv \nSelect and explain. \nA. P24, B. P17, C. P7, D. P14', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ref Robbins 7/e p246; 9/e p245 p24 antigen assay: It is available only as a blood test. It detects the HIV antigen called p24 plus antibodies to HIV-1 and HIV-2. ... The level of p24 antigenand the amount of virus (viral load) increase significantly soon after initial infection. Testing for p24 allows for detection of early infections, before HIV antibody is produced', 'role': 'assistant'}]