Haemoglobin A (HbA)
- Main type of Hb in adult blood
- Comprised of 2 alpha and 2 beta chains
Haemoglobin A2 (HbA2)
- 1.5 to 3% of adult blood
- 2 delta chains instead of 2 beta chains
Fetal haemoglobin (HbF)
- Main type of Hb during intrauterine development
- Levels reduce during infancy to around 0.5% in adult venous blood
- Hb affinity for CO more than 200 times greater than for oxygen – this means it displaces oxygen and is only slowly released
- Normal range in non-smokers is < 1.5% adult venous blood
- In smokers levels up to 5% adult venous blood
- Formed when the iron within haemoglobin is oxidied to the ferric state (FE3+)
- Not able to participate in respiratory function as it cannot bind oxygen
- Normal levels < 1% adult venous blood
- In adult venous blood this is usually around 70%
- Can be used as a measure of haemolysis
- Normal levels in adult venous blood < 0.00004%
- Levels can be impacted by phlebotomy technique
- Goljan, EF. (2014) Rapid Review: PathologyPhiladelphia: Elsevier Saunders.
- Rhoades, RA and Bell, DR. (2009) Medical Physiology: Principles for Clinical MedicinePhiladelphia: Wolters Kluwers.
- Hammond, E and McIndoe, A. (1997) QBase Anaesthesia: Volume 1, MCQs for the Anaesthesia Primary: MCQs for the Primary FRCA v. 1. London: Greenwich Medical Media.
- Na, N, et al. (2005) Serum free hemoglobin concentrations in healthy individuals are related to haptoglobin type. Clinical Chemistry, 51(9), 1754-1755.
Oxygen dissociation curve
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