Tip
When oxygen supply is insufficient, the body initially reduces the affinity of red blood cells for oxygen, ensuring adequate oxygen supply to peripheral tissues.
- Causes of shift to the right include:
- ↑ Partial pressure of carbon dioxide (↑ PCO2)
- ↑ Body temperature (e.g., fever)
- ↑ H+ (↓ pH)
- ↑ 2,3-BPG (generated by 2,3-BPG mutase during erythrocyte glycolysis)
- 2,3-bisphosphoglycerate (2,3-BPG) concentrations increase in erythrocytes when oxygen availability is reduced, as occurs in chronic lung disease, heart failure, and chronic exposure to high altitudes.
- ↑ Exercise
- ↑ Altitude
- Causes of shift to the left include:
- ↓ Partial pressure of carbon dioxide (PCO2)
- ↓ Body temperature
- ↓ H+ (↑ pH)
- ↓ 2,3-BPG (e.g., due to mutations in the BPGM gene on chromosome 7)
- ↑ CO
- ↑ Methemoglobin
- ↑ Fetal hemoglobin (HbF)