Microcytic anaemia

This is a type of anaemia where the mean cell volume (MCV) is less than 80 femtolitres (normal range = 80-100 fL).

The average erythrocyte is seen smaller than normal and much smaller than a leukocyte. Microcytic cells can appear to have a large area of central pallor.

The most common cause of microcytic anaemia is iron deficiency anaemia*. This shows a microcytic, hypochromic blood film with anisocytosis and poikilocytosis.

* NICE guidance states (2):

• if iron-deficiency anaemia and aged 60 and over then refer people using a suspected cancer pathway referral (for an appointment within 2 weeks)
• iron-deficiency anaemia (unexplained) with rectal bleeding in adults under 50 then consider a suspected cancer pathway referral (for an appointment within 2 weeks)
• if iron-deficiency anaemia without rectal bleeding in adults under 60 then offer testing for occult blood in faeces (FIT)

Note that reference ranges may vary between laboratories.

References:

• (1) Maner BS, Moosavi L. Mean Corpuscular Volume. [Updated 2021 Jul 10]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK545275/
• (2) NICE (June 2015). Suspected cancer: recognition and referral (accessed on 9/5/2022)