Predictors of Pain in Sickle Cell Disease

All participants must be between 15 and 40 years old and must be able to provide informed, written consent (for adults) or parental consent (for participants younger than 18 years). Inclusion Criteria: 1. Diagnosis of sickle cell disease (documentation of SS, SC, S beta + thalassemia, S beta + thalassemia) is required 2. Participants must have had at least one sickle cell related pain episode that required treatment with opioids at home or in the hospital 12 months prior to recruitment 3. Participants who are on chronic analgesics (NSAID, acetaminophen) or opioids should be on a stable dose for 4 weeks prior to recruitment. Exclusion Criteria: 1. Age less than 15 or greater than 40 years 2. Participants lacking the cognitive or mental capacity to assent to and complete study procedures 3. Pregnant females 4. Participants with history of a stroke with ongoing physical impairment that prevents participation in study procedures. 5. Participants with history of severe vaso-occlusive pain crisis resulting in either evaluation in an emergency department or admission to a hospital two weeks prior to study enrollment. 6. Current or active infection 7. Any condition that the principle investigator considers would preclude or bias participation in the study, such as (1) neuropathy from diabetes or other causes, (2) active avascular necrosis requiring treatment for pain