The chloride shift occurs in response to
HCO3−
The chloride shift occurs in response to bicarbonate ions (HCO3−). Most of the bicarbonate ions diffuse into the plasma of the blood during the transport of carbon dioxide. To restore the ionic balance, equal amounts of chloride ions diffuse inside the RBCs from the plasma. The exchange of bicarbonate ions of RBCs and chloride ions of the plasma is called the chloride shift or Hamburger shift.