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: Medicine
[{'content': 'The first virological marker following acute infection with HBV is : \nSelect and explain. \nA. HBs Ag, B. Anti HBs Ag, C. IgM anti FIBc Ag, D. Anti HBe Ag', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Answer is A (H Bs Ag): The earliest marker appearing in serum in acute Hepatitis B infection is HBs Ag. After infection the first virological marker detectable in serum is -- HBsAgQ - it precedes elevation of serum aminotransferases as well as clinical symptoms. Q - it remains elevated during the entire icteric or symptomatic phase of acute hepatitis B & beyond. Q Anti Hbs Ag appears only after Hbs Ag has disappeared (occasionally after a gap of several weeks). IgM Anti 14BcAg is demonstrable in serum beginning within 1-2 weeks after the appearance of HBsAg. e HBcAg is sequestrated and not detectable routinely in the serum. Q Anti I-IBe Ag appears sholy before disappearance of Hbs Ag. HBeAg appear concurrently or sholy after HBsAg Q.This too is detectable during the acute phase.', 'role': 'assistant'}]