Oxygen dissociation curve shifts to right in all except

Hb-O2 dissociation curve shift to left indicates more affinity of Hb to O2, and thus less delivery of O2 to tissues. In stored blood, 2,3 DPG levels are decreased.   Shift to left seen in -        Increased pH -        Decreased 2,3 DPG, temperature, PCO2 -        HbF (Fetal)   Shift to right seen in -        Decreased pH -        Increased 2,3DPG, temperature, PCO2 -        HbS (Sickle cell)