Inclusion Criteria:  need for CRRT, no contraindication to CRRT  Exclusion Criteria:  patients with previous history of chronic kidney disease (CKD) (baseline serum creatinine > 2 mg/dL (male) or > 1.5 mg/dL (female) history of renal transplantation known pregnancy previous dialysis within 30 days severe liver disease end stage heart disease or untreatable malignancy moribund patients with expected survival less than 30 days previous use of heparin or other anticoagulant, antiplatelet within 7 day except use for deep vein thrombosis active bleeding at the time of enrollment and/or severe coagulopathy receiving blood or blood components prior to enrollment hemoglobin less than 7.5 g/dL and/or platelet count less than 100,000/mm3 previous underlying clotting disorders such as hypercoagulable state severe malnutrition (Body mass index (BMI ) less than 18) underwent CRRT for other reasons besides acute kidney injury (AKI)