hypochromic microcytic anaemia - diferentiation via laboratory investigations
Last reviewed 01/2021
Laboratory investigations can help differentiate the cause of a hypochromic microcytic anaemia:
| iron deficiency | chronic nflammation or malignancy | thalassaemia (alpha or beta) | sideroblastic anaemia | |
mean cell volume (MCV); mean corpuscular haemoglobin (MCH) | both reduced in relation to severity of anaemia | mild reduction or low normal | both reduced; very low for degree of anaemia | very low in congenital type of sideroblastic anaemia - however MCV often increased in acquired form |
| total iron binding capacity (TIBC) | increased | reduced | normal | decreased or normal |
| serum iron | reduced | reduced | normal | normal or increased |
| serum ferritin | reduced | normal or increased | normal | increased |
| erythroblast iron | absent | absent | present | ring forms |
| bone marrow iron stores | absent | present | present | present |
| haemoglobin electrophoresis | normal | normal | Hb A2 increased in thalassaemia beta | normal |
Notes:
- in thalassaemia trait - red cells tend to be small (often MCV of 60 fl or less) even when anaemia is mild or absent
- in iron deficiency the indices fall progressively in proportion with the degree of anaemia
- in anaemia of chronic disorders the indices are markedly low - MCV is usually in the range 75-82 fl
- if iron deficiency anaemia is diagnosed then further investigation is mandatory to discover the cause of iron deficiency