This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Fluids and Electrolyte Imbalance, Subject name: Medicine
Anion gap is increased in all except? 
Select and explain. 
A. Renal tubular acidosis, B. Diabetic ketoacidosis, C. Acute tubular necrosis, D. Ethylene glycol poisoning
A: Renal tubular acidosis
Answer: A: Renal tubular acidosis 
Explanation: Anion gap: The anion gap is the difference between primary measured cations and the primary measured anions in serum. AG= Na-(Cl- + HCO3-) Value of Normal anion gap= 10 to 12 mmol/L Anion gap is increased in: Diabetic ketoacidosis Acute tubular necrosis Ethylene glycol poisoning