 Chronic blood transfusions are essential supportive care for sickle cell patients at high risk for morbidity and mortality due to stroke. These patients, however, are at risk for iron overload. In the investigators comprehensive sickle cell center, the investigators support chronic transfusion with rapid manual partial exchange transfusions RMPET using a single access central line port. The investigators do not have a comprehensive adult sickle cell program but upon transition of patients the patients would be provided simple transfusion ST in an adult ambulatory infusion setting due to nursing acuity needed for RMPET. The investigators plan to study the institutions participants currently on chronic transfusion support and compare different transfusion modalities to better understand the effects from switching from RMPET to ST. To date, there are no such comparisons within and between sickle cell patients in the literature. 