Hemoglobin electrophoresis
A test that separates the different types of haemoglobin in the blood and reports each as a percentage. It is the key test for diagnosing inherited haemoglobin disorders — thalassaemia, sickle-cell disease and other abnormal haemoglobins — by revealing which types are present and in what proportion.
What it measures
Haemoglobin is the protein in red blood cells that carries oxygen, and there are several normal types: adult haemoglobin (HbA) makes up most of it, with a small amount of HbA2 and, in adults, only traces of fetal haemoglobin (HbF). Hemoglobin electrophoresis (or the modern equivalent, HPLC) separates these types and any abnormal ones and reports each as a percentage. Its purpose is to diagnose inherited disorders of haemoglobin, called haemoglobinopathies. In beta-thalassaemia trait, HbA2 is characteristically raised and HbF may be too. In sickle-cell disease and trait, an abnormal haemoglobin (HbS) appears that would not be there normally. Other variants (such as HbC or HbE) can also be identified. It is used to investigate a long-standing microcytic anaemia that iron does not explain, as part of screening in pregnancy and before conception (especially where these conditions are common), and in newborn screening. The result is read as a whole pattern of percentages, together with the blood count, rather than as a single number.
What a high value can mean
- A raised HbA2 — the hallmark of beta-thalassaemia trait.
- Presence of HbS — sickle haemoglobin, indicating sickle-cell trait or disease depending on the amount.
- A raised HbF (fetal haemoglobin) — seen in some thalassaemias and other conditions.
- Other abnormal haemoglobins (HbC, HbE, and more) — identified by their distinct pattern.
What a low value can mean
- A normal adult pattern — mostly HbA with a small normal HbA2 and trace HbF; no abnormal haemoglobin detected.
- Note: a normal HbA2 does not fully exclude alpha-thalassaemia, which may need separate genetic testing.
When to discuss with a doctor
Hemoglobin electrophoresis is a diagnostic test rather than one to act on urgently. It is used to explain a persistent microcytic anaemia that is not due to iron deficiency, to confirm a suspected inherited haemoglobin disorder, and for screening before or during pregnancy and in newborns. Its results guide genetic counselling — knowing whether both partners carry a trait matters for the risk to children — and, in the case of sickle-cell or a significant thalassaemia, ongoing specialist care. Because the result is a pattern interpreted alongside the blood count and family origin, and because carrier states usually cause no symptoms, it is understood within haematology and genetic counselling. Mediora.AI can show the electrophoresis pattern alongside the blood count and iron studies so the picture is read together; the diagnosis and counselling belong with your doctor.