22nd May 2023

Normal erythrocyte morphology

Erythrocytes (i.e. red blood cells) are the commonest type of blood cell. They lack a nucleus and other organelles but are rich in haemoglobin, which is responsible for transporting oxygen and carbon dioxide in the circulation. Normal erythrocytes are flexible, biconcave discs. This structure creates a large surface area to volume ratio for optimal gas exchange within tissues, whilst facilitating easy movement through narrow blood vessels.

Abnormalities in size, shape, colour, or distribution of erythrocytes can indicate an underlying disease process. Poikilocytosis refers to abnormalities in the shape of erythrocytes, whereas anisocytosis refers to the presence of varying sizes of erythrocytes.