Anaemia

Overview

Anaemia is a condition in which the haemoglobin in the blood is below the normal range, so the blood carries less oxygen to the body than it should. It is not a single disease but a sign that red blood cells are reduced in number, in oxygen-carrying capacity, or both. Anaemia is extremely common, often silent in its early stages, and usually first found on a routine complete blood count. This is the main canonical page for anaemia; the more specific angles — low haemoglobin as a test result, the deficiency causes, the red-cell patterns and the symptoms anaemia produces — each have their own focused pages that link from here.

How anaemia is defined

Anaemia is defined by haemoglobin below the reference range for age and sex — roughly below 13 g/dL in adult men and below 12 g/dL in adult non-pregnant women, with lower thresholds in pregnancy and slightly different ranges in older adults. The severity is graded as mild, moderate or severe based on how far below the range the value falls. A single reading is interpreted alongside the red-cell indices, the rest of the blood count, and the clinical picture, not in isolation.

The three guiding questions

• How low is the haemoglobin — mild, moderate or severe?
• What pattern do the red cells show — small (microcytic), large (macrocytic) or normal-sized (normocytic)?
• What is the mechanism — reduced production, blood loss, or increased breakdown?

Answering these three questions narrows the cause and directs the tests. The red-cell size (MCV) is particularly useful: microcytic anaemia points towards iron deficiency or thalassaemia; macrocytic anaemia towards B12 or folate deficiency; and normocytic anaemia towards chronic disease, kidney disease, early iron deficiency or bone marrow causes. See Microcytic Anaemia, Macrocytic Anaemia and Normocytic Anaemia.

Common causes

• Iron deficiency — the commonest cause (see Iron Deficiency Anaemia).
• Vitamin B12 or folate deficiency (see Vitamin B12 Deficiency, Folate Deficiency).
• Blood loss — menstrual, digestive or other (see Digestive Problems).
• Anaemia of chronic disease — inflammation, kidney or autoimmune disease (see Kidney Health).
• Haemolytic anaemia — increased red-cell breakdown.
• Bone marrow causes — less common, needing specialist assessment.

Symptoms

Mild anaemia often causes no symptoms. As it worsens, tiredness, exertional breathlessness, palpitations, dizziness, paleness and cold extremities appear. The speed of the fall matters as much as the level — a gradual drop is better tolerated than a rapid one. See Fatigue Due to Anaemia, Weakness Due to Low Haemoglobin and Breathlessness Due to Anaemia.

Evaluation and investigations

Evaluation starts with the complete blood count and a peripheral smear, then adds targeted tests based on the red-cell pattern — iron studies for microcytic anaemia, B12 and folate for macrocytic anaemia, and reticulocyte count, kidney and thyroid function, inflammatory markers and a stool check for hidden blood for normocytic anaemia. Tests are chosen from the pattern, not ordered as a blanket panel. See Abnormal Complete Blood Count (CBC) and Abnormal Test Results.

Management overview

Management treats the cause: iron for iron deficiency anaemia with the source of loss addressed, B12 or folate for the relevant deficiency, and treatment of the underlying condition for anaemia of chronic or kidney disease. Transfusion is reserved for severe, symptomatic or rapidly developing anaemia. The response is confirmed with repeat testing, and treatment is continued until stores are replenished. See Iron Deficiency Anaemia and Nutritional Anaemia.

Warning signs — seek prompt care

• Severe breathlessness, chest pain or fainting with a very low haemoglobin.
• Black or bloody stools suggesting ongoing bleeding.
• A haemoglobin falling rapidly on repeat testing.

How we help

Dr. Nayak identifies the pattern and cause of your anaemia, orders focused tests, and builds a cause-specific plan with monitoring to confirm the response and prevent recurrence. Consultations are available in-clinic in Bhubaneswar and over teleconsultation.

Related conditions and patient concerns

• Low Haemoglobin
• Iron Deficiency Anaemia
• Microcytic Anaemia
• Macrocytic Anaemia
• Normocytic Anaemia
• Nutritional Anaemia
• Abnormal Complete Blood Count (CBC)
• Fatigue, Weakness & General Symptoms
• Digestive Problems
• Kidney Health