Acetate-free bicarbonate dialysate: Which acid in the dialysis buffer?

The mix of bicarbonate and divalent cations requires a small amount of acid to avoid insoluble precipitation in the dialysate buffer. Small doses of acetic acid (3–7 mmol/L) are commonly used. Acetic acid may be replaced by hydrochloric acid or citric acid to achieve acetate-free haemodialysis. Hydrochloric acid theoretically avoids metabolic side effects of acetate. However, additional cost generated by technical constraints probably slowed its generalization. Citric acid has been proposed as a more biocompatible acidifier than acetic acid. By binding calcium, citric acid inhibits both coagulation and complement activation and may reduce the treatment-induced inflammatory response. However, results of the study are conflicting, especially regarding impact on calcium and phosphate metabolism and acid-base metabolism. On the basis of current findings, systematic replacement of acetic acid by citric acid cannot be proposed for all the patients.