Renal tubular acidosis is best described as which type of metabolic acidosis?

• A. High Aion Gap Metabolic Acidosis
• B. Normal Anion Gap Metabolic Acidosis
• C. Metabolic Alkalosis
• D. Respiratory Acidosis

Answer: (B)

Renal tubular acidosis produces a metabolic acidosis with a normal (non-elevated) anion gap. In RTA, the kidneys fail to acidify the urine or reclaim enough bicarbonate, causing bicarbonate loss and a rise in chloride to maintain electroneutrality. That keeps the measured anion gap (sodium minus the sum of chloride and bicarbonate) within the normal range, yielding a hyperchloremic, normal-anion-gap metabolic acidosis. This contrasts with high anion gap metabolic acidosis, where unmeasured anions (like lactate, ketoacids, or toxins) raise the gap. So, the hallmark description is a normal anion gap metabolic acidosis.