Inclusion Criteria:

1. End Stage Renal Disease 18 yrs or older.
2. CVCD with average dialysis flow rate over 300 mL/min for three most recent visits.
3. Expectation by Investigator that CVCD may be needed for up to 26 weeks.
4. Dialysis catheter is of three types a) single body with single entry and exit, b) single body with split ends, c) twin catheter with one catheter for removal of blood and another for return.
5. Kt/V >1.1 or equivalent URR
6. Negative serum pregnancy unless surgically sterile or post menopausal for >1yr.
7. Negative blood culture result from pre-enrollment blood sample draw.
8. Ability of patient to sign and understand the informed consent.
9. Most recent lab results don't indicate hypocalcemia (<7mg/dL) or thrombocytopenia (<20,000)
10. Avg. systolic blood pressure >90 mmHg as measured during the most recent three dialysis treatments.
11. Lack of signs of current blood stream infection at the beginning of the prior three dialysis treatments.

Exclusion Criteria:

1. A known Heparin allergy or a history of type 2 (antibody mediated) Heparin-induced thrombocytopenia.
2. Active bleeding from any site or a documented positive stool hemocult test within 28 days of enrollment in study.
3. Bloodstream infection,exit site infection or any infection requiring antibiotic use within 14 days of enrollment for any antibiotic listed in section 4.2.3 or within 30 days of enrollment for Vancomycin or any other antibiotic not listed in section 4.2.3 of the protocol
4. Inability to comply with the conditions of, or complete the protocol in the opinion of the Investigator.
5. Pregnant or breast feeding.
6. Documented allergy to sodium citrate, methylene blue, methyl/paraben and/or propyl paraben.
7. Documented chronic intrinsic coagulopathy evidenced by persistently and significantly elevated Prothrombin (INR>3), Partial Thromboplastin Time (PTT>60 seconds), or thrombocytopenia (platlet count <20,000/mm).
8. Malignancy requiring chemotherapy or radiation treatment within 180 days of enrollment.
9. Documented requirement for >5,000 units of Heparin per catheter lumen to maintain catheter patency (with decrease in blood flow demonstrated at 5,000 units per lumen Heparin catheter lock) with current catheter.
10. Contraindications to citrate or taking drugs that may interact with citrate.
11. Documented history of glucose-6-phosphate dehydrogenase deficiency (G6PD or Drug-induced methemoglobinemia).
12. Participation in another research study.
13. Co-morbidities, such as HIV, active hepatitis or recent transplants, that in the opinion of the Investigator, may increase the risk associated with study participation or may interfere with the interpretation of study results and would make the subject inappropriate for entry into this study.
14. Unknown priming volume of catheter lumens.
15. Redness of over 1 cm diameter or pus around the catheter exit site.