An alternative to systemic heparin anticoagulation for HD is citrate dialysate (CD). CD contains a small amount of citric acid rather than acetic acid as the acidifying agent. The use of citrasate may lead to lower heparin requirements in hemodialysis. This is a randomized, double blinded, two-period crossover trial in HD patients to compare the effect of citrasate dialysis (CD) and usual acetic-acid based dialysate (AD) on heparin dose.

The investigators will perform a randomized, double-blind, two-period crossover trial in chronic HD patients to compare the effect of citrasate dialysate (CD) and usual acetic-acid based dialysate (AD) on the cumulative intradialytic heparin dose. There is a four week run in phase followed by two weeks of intervention AD or CD followed by the remaining AD or CD intervention.

The primary outcome is change in intradialytic heparin dose achieved with citrasate compared with acetate dialysate. Secondary outcomes are the effect of CD compared with AD on systemic anticoagulation, bleeding time after HD, metabolic parameters, dialysis adequacy, inflammation, hemodynamic stability, and intra-rater and inter-rater reliability of the dialyzer clotting score.

Inclusion Criteria:

• chronic stable HD patients ≥ 18 years
• on HD at least three times per week for at least 3 months

Exclusion Criteria:

• contraindication to heparin
• currently using heparin-free HD
• known clotting disorder
• on warfarin therapy
• dialyzing with a dysfunctional central venous catheter (blood flow rates consistently less than 300mL/min and/or frequent use of thrombolytic)
• history of vascular access dysfunction
• planned vascular access conversion or procedure during the study period
• use of high calcium dialysate
• active medical issue requiring hospitalization
• planned kidney transplant during the study period
• planned conversion of dialysis modality (peritoneal dialysis, nocturnal dialysis) during the study period
• unable to provide informed consent