Certified clinical Laboratories at each site will analyze all blood samples. Blood work at our site will be done at the Autonomic Research Laboratory at ICORD. A trained technician will draw a venous blood sample. Participants will undergo a 12-hour fast the night before, including no food or drink including alcohol or caffeine (water is permitted). A complete blood count (white blood cells and differentials, erythrocytes, packed cell volume, hematocrit, platelets, hemoglobin and red cell indices) will be performed.