ABSTRACT
In renal tubular acidosis (RTA) there is a failure to acidify urine to a level appropriate for blood pH; systemic acidosis is therefore not corrected. Unlike renal failure, anions such as sulphate and phosphate are filtered normally and are therefore unavailable to balance the loss of bicarbonate; electrical neutrality is instead maintained by renal chloride absorption, resulting in a hyperchloraemic metabolic acidosis with a normal anion gap.
