Case Presentation: A 17yo female with sickle cell disease (SCD; HbSS genotype) presented with pain crisis and acute chest syndrome. She was treated with appropriate antibiotics (ceftriaxone/cefdinir and azithromycin). During the first few days of her hospitalization, she required 2 pRBC transfusions for down trending hemoglobin (Hb) and low reticulocyte count. On hospital day 11, [...]