This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: miscellaneous, Subject name: Biochemistry
[{'content': 'Which of the following is not normally excreted in urine? \nSelect and explain. \nA. Sodium, B. HCO3, C. Creatinine, D. Uric acid', 'role': 'user'}, {'content': 'Answer: B \nExplanation: The hydrogen ions secreted into the luminal fluid is required for the reabsorption of filtered bicarbonate.Bicarbonate is filtered by the glomerulus. This is completely reabsorbed by the proximal convoluted tubule so that the urine is normally bicarbonate-free.Ref: D M Vasudevan 7th edition Page no: 396', 'role': 'assistant'}]