What does the Complete Blood Count with Differential and Erythrocyte Indices test measure?

Why is Complete Blood Count with Differential and Erythrocyte Indices measured?

The CBC anchors the anaemia panel by establishing whether anaemia is present (haemoglobin below the sex-specific lower limit), quantifying its severity, and providing the morphological classification through MCV — microcytic anaemia (MCV <80 fL) directs investigation toward iron deficiency, thalassaemia, anaemia of chronic disease, and sideroblastic anaemia; normocytic anaemia (MCV 80–100 fL) toward haemolysis, anaemia of chronic disease, early mixed deficiency, and bone marrow failure; macrocytic anaemia (MCV >100 fL) toward vitamin B12 deficiency, folate deficiency, hypothyroidism, liver disease, and medication effect. RDW elevation — the earliest haematological change in iron, B12, and folate deficiency — precedes MCV change and provides additional discrimination power, with elevated RDW in a normocytic anaemia suggesting a mixed deficiency pattern.

Reference ranges

Standard reference

Hgb (F): 11.5–15.5 g/dL; Hgb (M): 13.5–17.5 g/dL; MCV: 80–100 fL; MCH: 27–33 pg; MCHC: 32–36 g/dL; RDW: 11.5–14.5%; Platelets: 150–400 ×10³/µL # REVIEWER FLAG: Confirm Access Medical Laboratories sex-specific and age-stratified reference ranges for all CBC sub-components — particularly haemoglobin, haematocrit, and RBC, which differ materially between sexes and across age groups.

Functional medicine optimal

Haemoglobin (F): 13.0–15.5 g/dL; Haemoglobin (M): 14.5–17.0 g/dL (functional medicine optimal for maximal oxygen transport capacity); MCV: 85–95 fL; RDW: <13.0% (lower RDW indicates erythrocyte population homogeneity consistent with nutritional adequacy). # REVIEWER FLAG: Functional optimal ranges for erythrocyte parameters are not standardised in mainstream haematology — reviewer to confirm appropriate framing.

Units

Hgb: g/dL, Hct: %, RBC: ×10⁶/µL, MCV: fL, MCH: pg, MCHC: g/dL, RDW: %, WBC: ×10³/µL, Platelets: ×10³/µL

Reference ranges vary by laboratory and assay platform. Interpret in context of the issuing laboratory's stated range.