An 7 year old with sickle-cell disease had been inpatient te…

An 7 year old with sickle-cell disease had been inpatient ten days prior, and received a transfusion of 2 units packed red blood cells. The child now presents to  the ED with back pain and increased scleral icterus.   When the patient was discharged from the hospital, the Hb was 10 gm/dL and is now 6 gm/dL on today’s admission. The DAT is 3 + for IgG.  The most likely situation at this time is: