This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Nephrology, Subject name: Medicine
[{'content': 'Which one of the following studies is most sensitive for detecting diabetic nephropathy in early stage? \nSelect and explain. \nA. Microalbuminuria, B. Creatinine clearance test, C. Ultrasonography, D. Serum creatinine level', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Microalbuminuria is defined as excretion of 30-300 mg of albumin per 24 hours (or 20-200 mcg/min or 30-300 mcg/mg Creatinine) on 2 of 3 urine collections. The detection of low levels of albumin excretion (Microalbuminuria) has been linked to the identification of incipient diabetic kidney disease. This phase calls for aggressive management to prevent or retard ove diabetic nephropathy.', 'role': 'assistant'}]