Inclusion Criteria:  Pediatric patients ages 6 months - 17 years Currently followed in the CKD clinic at Children's Healthcare of Atlanta (CHOA) Diagnosed with Stage 3, Stage 4 or Stage 5 CKD Must have routine venous laboratory tests planned as a component of their clinic encounter.  Exclusion Criteria:  Participants <13.6kg (to allow for safe blood sample volumes). History of venous thromboembolism, post solid organ transplant, co-diagnosis of inflammatory disease, and nephritis. Personal or family history of inherited thrombophilia conditions Hospital admission within the last 30 days. Transfusion (PRBC, FFP, Platelets, or Cryoprecipitate) within the last 30 days. Those on the following medications: steroids and anti-coagulants.