Inclusion Criteria:  Critically ill ALF or ACLF adult patients with AKI aged ≥ 18 y old Currently receiving CRRT.  Exclusion Criteria:  severe acidosis (pH < 7.1) or severe alkalosis (pH > 7.55) blood transfusion within 24 h prior to the study use of citrate-containing medications severe hypocalcemia (serum ionized calcium < 0.8 mmol/L) use of heparin as anticoagulation