Microcytic Anaemia

Overview

Microcytic anaemia is anaemia in which the red cells are smaller than normal, shown by a low mean corpuscular volume (MCV) on the blood count. The pattern is a clue to the cause rather than a diagnosis itself. This page focuses on the microcytic pattern and its evaluation; the commonest cause — iron deficiency anaemia — and its treatment are covered on the Iron Deficiency Anaemia page.

Main causes

• Iron deficiency anaemia — by far the commonest cause (see Iron Deficiency Anaemia).
• Thalassaemia and related haemoglobin disorders — inherited, often mild and found on routine testing.
• Anaemia of chronic disease — can occasionally be microcytic.
• Sideroblastic anaemia and lead poisoning — less common.

Why the pattern matters

A low MCV narrows the list of causes and directs the tests. Iron studies (ferritin, serum iron, transferrin saturation) confirm or exclude iron deficiency. If iron studies are normal or high despite small cells, thalassaemia is considered — especially in people of South Asian, Mediterranean or African origin — and a haemoglobin electrophoresis is arranged. Distinguishing the two matters because iron deficiency is treated with iron, while giving iron to someone with thalassaemia trait is unnecessary and can cause iron overload. See Iron Deficiency Anaemia and Iron Deficiency.

Evaluation and investigations

A complete blood count with indices and a peripheral smear is the starting point, followed by iron studies. Haemoglobin electrophoresis is added when thalassaemia is suspected. The cause of any iron loss is sought in parallel. See Abnormal Complete Blood Count (CBC) and Abnormal Test Results.

Management overview

Management follows the cause: iron replacement and source control for iron deficiency anaemia, and no iron treatment (with genetic counselling where relevant) for thalassaemia trait. The response is confirmed with repeat counts. See Iron Deficiency Anaemia and Anaemia.

Warning signs — seek prompt care

• A microcytic anaemia with black or bloody stools — possible digestive bleeding.
• A haemoglobin falling despite iron treatment — review the diagnosis and cause.

How we help

Dr. Nayak uses the microcytic pattern to distinguish iron deficiency from thalassaemia and other causes, orders the right confirmatory tests, and builds a cause-specific plan. Consultations are available in-clinic in Bhubaneswar and over teleconsultation.

Related conditions and patient concerns

• Anaemia
• Iron Deficiency Anaemia
• Iron Deficiency
• Macrocytic Anaemia
• Normocytic Anaemia
• Abnormal Complete Blood Count (CBC)