Lab Tests for Anaemia
Anaemia means your blood is carrying less oxygen than it should. But anaemia has many causes — iron deficiency, B12 deficiency, chronic disease, or blood cell disorders. These tests identify which type you have and how severe it is.
Clinical overview
A low haemoglobin on a CBC tells you anaemia exists, but not why. The cause determines the treatment — which is why a second panel of tests is always needed. The pattern of results (cell size, iron stores, vitamin levels) narrows the diagnosis rapidly.
Primary tests ordered for Anaemia
These are the tests most commonly ordered first when anaemia is suspected or being monitored.
Complete Blood Count (CBC)
Your CBC came back with flags on multiple values. The report is a wall of numbers and you…
Haemoglobin (Hgb / Hb)
Your haemoglobin came back low — or flagged. It's the single most important number in your blood test…
MCV, MCH & MCHC (Red Cell Indices)
These three numbers often appear on your CBC without explanation. Together they tell your doctor exactly what kind…
Iron Studies (Ferritin, Iron & TIBC)
A low haemoglobin can have many causes. Iron studies — ferritin, serum iron, TIBC, and transferrin saturation —…
What to expect
- 🩸 The first test is always a full CBC — haemoglobin, MCV, RBC, and haematocrit.
- 📐 MCV (cell size) directs the investigation: low = iron; high = B12/folate.
- 🧪 Iron studies (ferritin, TIBC) confirm or exclude iron deficiency.
- ⏰ No fasting required for most anaemia tests.
- ⌛ Iron replacement typically takes 8–12 weeks to normalise haemoglobin.
Testing frequency
Also commonly ordered
These tests are frequently added to the primary panel based on initial results or specific clinical circumstances.
Vitamin B12
B12 deficiency causes large red cells (high MCV) — megaloblastic anaemia.
Folate
Folate deficiency also causes macrocytic anaemia, often alongside B12 deficiency.
Reticulocyte Count
Immature RBCs indicate whether the bone marrow is actively producing cells.
Thyroid Function (TSH)
Hypothyroidism is a common cause of mild anaemia — especially macrocytic.
Blood Film
Microscopy identifies abnormal cell shapes: sickle cells, target cells, spherocytes.
Haemoglobin Electrophoresis
Confirms thalassaemia, sickle cell disease, and other haemoglobin variants.
Urgent result thresholds
These result patterns require prompt clinical attention — always discuss with your doctor rather than interpreting alone.
Severe anaemia — urgent investigation. Transfusion may be required.
Severe microcytosis — investigate for thalassaemia or severe iron deficiency urgently.
Acute blood loss or haemolysis — requires urgent hospital assessment.
Empty iron stores — oral iron replacement should begin immediately.
Medical Disclaimer: This guide is for educational reference only. It does not constitute medical advice and should not replace consultation with a qualified healthcare professional. Always discuss your test results with your doctor. Full disclaimer →