Haemoglobin

Haemoglobin (Hb) is a tetrameric protein in red blood cells (RBCs) — each molecule consists of four globin chains, each containing an iron-bound haem group that reversibly binds one oxygen molecule. This allows each RBC to carry four oxygen molecules. Haemoglobin picks up oxygen in the high-oxygen environment of the lungs and releases it to oxygen-hungry tissues throughout the body.

Normal haemoglobin ranges: adult men 130–170 g/L, adult women 120–155 g/L, children (varies by age). Low haemoglobin = anaemia (see Anaemia entry). High haemoglobin (polycythaemia) may indicate chronic hypoxia (COPD, sleep apnoea, high altitude), dehydration, or polycythaemia vera (a rare bone marrow disorder). Glycated haemoglobin (HbA1c) reflects average blood glucose over the preceding 2–3 months and is the key monitoring and diagnostic test for diabetes.

Haemoglobin variants and disorders relevant to Korea's population include aplastic anaemia (bone marrow failure affecting all blood cell lines), which has a notably higher incidence in East Asian populations than in Western populations, and thalassaemia trait, which occurs at low but non-negligible rates. Genetic counselling is available through major hospital haematology departments for families with a known history of inherited blood disorders.