Microcytic and Hypochromic Red Cells
From haematologyetc.co.uk
Derivation: From the Greek hypo [under} and New Latin chromia [state of pigmentation]
Appearance
A cell containing insufficient haemoglobin – best detected as an increase when the area of pallor iof the erythrocyte extends beyond one third of the red cell diameter. The appearance tends to be obvious when the pallor exceeds half the cell diameter. In most circumstances hypochromic cells will also have reduced size (microcytosis).
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Image 1: Hypochromic red cell
The area of pallor in the center of the cell extends almost to the edge of the cell. The hypochromia indicates a reduced hemoglobin content. Hypochromatic cells are also generally small in size (microcytic).
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Image 2:
Hypochromic red cells montage:'Note the small size (compare with the nucleus of the small lymphocyte) on the image. In this case the image represents iron deficiency as indicated by the pencil cell (see the separate description).
Significance
The presence of hypochromia indicates defective production of haemoglobin. Most cases result from iron deficiency or thalassaemia – other typical features of these conditions should therefore be sought. Less frequently, hypochromia reflects defective iron utilisation (e.g. chronic disease or sideroblastic anaemia). The presence of hypochromia is not of itself an urgent problem unless there is severe anaemia; however, it important to highlight the condition since clinicians may need to request further investigation to determine its cause.
Pitfalls
Be sure you are viewing the correct area of the film – the central pallor is clearly shown only in the area where red cells first begin to contact each other. Poorly stained films may also be a problem – remember it is the extent of the area of pallor that is important not the stain colour. Finally, central pallor probably cannot be accurately assessed in damaged or abnormally shaped cells unless the hypochromia is very severe.
Further information
1. Go to Causes