This cross-sectional pilot study will examine the blood clotting patterns in children with chronic kidney disease stages 3, 4, and 5. A total of 30 participants will be enrolled with 10 participants for each stage of chronic kidney disease. Blood specimens will be collected from each participant during a routine clinic visit, and will then be processed to evaluate blood clotting characteristics according to thrombelastography and more conventional clotting tests.

Chronic kidney disease (CKD) is associated with 5% of all pediatric inpatient venous thromboembolism (VTE) occurrences, but rates of occurrence are likely underreported in current literature. VTE is associated with a 2-fold increase in mortality, and exponentially higher rates of healthcare expenditure. Because VTE is a low-incidence but high-impact complication of CKD, evaluating those at risk presents a unique challenge. The underlying pathophysiology of thrombosis in CKD is poorly understood, but likely involves changes across the hemostatic and fibrinolytic systems. Standard laboratory tests provide a poor representation of in-vivo clot formation, particularly in the complex hemostatic environment of CKD, as these tests undergo centrifugation and much of the cellular debris known to contribute to clot formation is lost. Viscoelastic assays are a reemerging tool that provide a qualitative measure of each hemostatic milestone, from clot formation through degradation, in whole-blood; thereby preserving the cellular debris and additional factors that contribute to clot formation in-vivo.

The purpose of this study is to evaluate the utility of Thrombelastography vs conventional clotting tests to predict onset of hypercoagulability and the relationship to the stage of pediatric Chronic Kidney Disease (CKD). The investigators hypothesize that as kidney function deteriorates, a more pronounced prothrombotic profile is expected to emerge according to TEG and conventional clotting tests. This will be demonstrated by an overall increase in measured values across the coagulation portion of the TEG and a decrease in the measured fibrinolysis. According to conventional clotting tests, it is expected to find increased levels of Factor VIII antigen, Fibrinogen, vWF, Protein C/S, and D-dimer. Depending upon an individual's degree of proteinuria, levels of Antithrombin would be expected to decrease as it is lost in the urine. This urinary loss of Antithrombin would also contribute to an overall prothrombotic profile.

This cross-sectional pilot study will enroll 30 participants between the ages of 6 months and 17 years who have been previously diagnosed with CKD stages 3, 4, or 5. Enrollment will occur during a routine clinic visit wherein the participant was also previously scheduled to receive venipuncture for ongoing monitoring of labs. Study specific lab values, in addition to routine lab values of interest and pertinent past medical history, will be extracted from the EMR.

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.

Previously established, and routinely followed, pediatric individuals between the ages of 6 months and 17 years with a non-inflammatory etiology of chronic kidney disease staged as 3, 4, or 5.