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
Two most impoant test to be done in a comatose patient with blood glucose of 750mg/d1 will be: 
Select and explain. 
A. Serum creatinine, B. Serum sodium, C. CSF examination, D. All
A: Serum creatinine
Answer: A: Serum creatinine 
Explanation: Answer is A (Serum creatinine) Presence of blood glucose of 750mg/d1 in a comatose patient suggests a possible diagnosis of non ketotic "hyperglycemic coma or diabetic ketoacidosis. Amongst the options provided estimation of blood pH will help establish a diagnosis of diabetic ketoacidosis while estimation of serum creatinine will help in establishing a diagnosis of hyperosmolar non ketotic coma as prerenal azotema is a characteristic feature of the latter.