<prompt> All of the following factors influence hemoglobin dissociation curve, exceptChloride ion concentrationCO2 tensionTemperature23 DPG levels  <response>: Hb-O2 dissociation curve shift to left indicates more affinity of Hb to O2 and thus less delivery of O2 to tissues.Shift to left seen in- Increased pH- Decreased 2,3 DPG, temperature, PCO2- HbF FetalShift to right seen in- Decreased pH- Increased 2,3DPG, temperature, PCO2- HbS Sickle cell 