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These three numbers often appear on your CBC without explanation. Together they tell your doctor exactly what kind of anaemia you have — or whether your red cells are functioning normally — without a single extra test.
Clinical Pathology, Hematology ·
The essentials — before you read the full guide below.
Mean Corpuscular Volume: average size of your red blood cells. Normal 80–100 fL. Low MCV (small cells) = microcytic. High MCV (large cells) = macrocytic.
Mean Corpuscular Haemoglobin: amount of haemoglobin per red cell. Normal 27–33 pg. Low MCH means pale, iron-poor cells (hypochromic).
Mean Corpuscular Haemoglobin Concentration: density of haemoglobin per red cell. Normal 32–36 g/dL. Low MCHC confirms hypochromia.
MCV identifies cell size; MCH and MCHC confirm haemoglobin content. Together they distinguish iron deficiency from B12/folate deficiency, thalassaemia, and other causes at a glance.
Reference Ranges
Use the interactive slider below, or read the range cards for a full clinical breakdown.
Drag to see what your MCV, MCH & MCHC (Red Cell Indices) means
The Science
Haematologists use MCV and MCH to classify anaemia into three types before ordering further tests. This classification — microcytic, normocytic, or macrocytic — narrows the differential diagnosis from dozens of possibilities to 3–5. It's one of the most efficient diagnostic shortcuts in clinical medicine.
Low MCV + low MCH + low MCHC is the textbook pattern of iron-deficiency anaemia. Thalassaemia trait also causes microcytosis but typically with a normal or high RBC count — a useful distinguishing feature.
High MCV prompts B12 and folate measurement. Both deficiencies cause megaloblastic changes — immature, oversized red cell precursors that fail to mature normally. Methotrexate and antiretrovirals also cause macrocytosis.
Red cell distribution width (RDW) measures variation in cell size. High RDW with low MCV suggests mixed iron and B12 deficiency — both pulling cell size in opposite directions.
When to Test
These are the most common reasons a MCV, MCH & MCHC (Red Cell Indices) test is requested — from symptoms to routine screening.
The most common indication. Low MCV with anaemia confirms the clinical suspicion and directs to ferritin and iron studies.
Primary useB12 deficiency causes both macrocytic anaemia and subacute combined degeneration of the spinal cord — numbness, tingling, and cognitive change.
B12 warningAlcohol directly causes macrocytosis — even without B12 or folate deficiency. Liver disease also elevates MCV.
Common causeThalassaemia trait is common in these populations and causes microcytosis — MCV 65–78 fL with a normal or elevated RBC count.
Genetic factorThese drugs interfere with DNA synthesis and cause macrocytosis. MCV monitoring is part of routine drug-induced haematological surveillance.
Drug causeMCV, MCH, and MCHC are automatically calculated and reported as part of every standard blood count.
Always includedTesting Schedule
Frequency depends on your current health status and your doctor's guidance.
Red cell indices are calculated from each CBC — no extra request needed.
MCV normalises within 8–12 weeks of successful iron replacement and 4–8 weeks of B12 therapy.
Annual CBC monitors haemoglobin level in known thalassaemia carriers — most need no treatment but baseline monitoring is standard.
Patients on methotrexate or hydroxycarbamide have MCV monitored as a surrogate for bone marrow toxicity.
If Your Result Is Abnormal
The indices direct the next panel of tests — rarely do they require repeat in isolation.
Ferritin, serum iron, and TIBC. Ferritin below 30 µg/L confirms iron deficiency even if haemoglobin is still normal.
Ferritin firstB12 below 200 pg/mL and folate below 5 ng/mL. Check homocysteine and methylmalonic acid if borderline — these confirm functional deficiency.
B12 + folate + TSHThis pattern (microcytosis with many small cells) is the classical thalassaemia trait profile. Haemoglobin electrophoresis or HPLC confirms the diagnosis.
Haemoglobin HPLCMCV below 60 or above 115 fL warrants a blood film. Haematologists look for target cells (thalassaemia), hypersegmented neutrophils (B12), and macro-ovalocytes.
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