The purpose of this study is to determine whether the use of Citrasate®, citric acid dialysate enables the reduction of the heparin N (anticoagulant) dose in patients undergoing hemodialysis.

During hemodialysis, waste products are removed from the blood by diffusion across the dialyzer membrane into an electrolyte solution known as dialysate. Dialysate is produced from acid concentrate, bicarbonate solution and water using a three stream proportioning system that mixes the acid concentrate, bicarbonate and water to produce the final dialysate. Patients are typically anticoagulated with heparin during dialysis to prevent blood from clotting in the extracorpoeial circuit. Heparin use is associated with significant risks including the possibility of bleeding, heparin induced thrombocytopenia (HIT) and contamination. For these reasons, the possibility of reducing heparin dose while maintaining HD adequacy is clinically attractive. Citrasate® is an FDA approved acid concentrate that contains citric acid (citrate) rather than acetic acid (acetate) which is traditionally used in acid concentrate. Citrate in higher concentrations is also a known anticoagulant. We are therefore conducting this study to determine whether the use of Citrasate, citric acid dialysate enables the reduction of the heparin requirements in patients undergoing hemodialysis.

Inclusion Criteria:

• Subject is capable of giving informed consent, or has an acceptable surrogate capable of giving consent on the subject's behalf.
• ESRD maintained on thrice weekly HD
• Stable Heparin prescription (Heparin dose) for the previous 4 weeks
• Dialyzed using bolus heparin anticoagulation with dose >/= 2000 units per treatment
• Hgb >/= 9.5 prior to study start
• eKt/V >/= 1.0 (or spKt/V >/= 1.2) in the monthly lab work prior to study start

Exclusion Criteria:

• Any laboratory abnormality, medical condition or psychiatric disorder which in the opinion of the investigator would put the subject's disease management at risk or may result in the subject being unable to comply with study requirements
• Patient is maintained on Coumadin therapy or LMW heparin
• Known history of HIT, coagulopathy or any other bleeding and/or thrombotic disorders
• Patients dialyzed with < 2000 units of Heparin per treatment
• Dialyzed without heparin
• Known pregnancy
• Dialyzed with reuse of hemodialyzers
• Documented clotted dialyzer or dialysis lines in last 30 days (1 month) requiring changing dialyzer, bloodlines or terminating treatment
• Randomized in a clinical trial involving anticoagulation in the last 30 days

Subjects will be recruited from the hemodialysis population in the participating facilities (study sites).