Main laboratory tests for the assessment of iron depletion
| Laboratory test | Normal values | ||
| Conventional units | Conversion factor† | SI units | |
| Iron status in the body | |||
| ▶Serum iron | 50–180 μg/dl | ×0.179 | 9–32 μmol/l |
| ▶Transferrin | 200–360 mg/dl | ×0.01 | 2–3.6 g/l |
| ▶Transferrin saturation | 20–50% | ||
| ▶Ferritin (Ft) | 30–300 ng/ml | ×2.247 | 65–670 pmol/l |
| ▶Soluble transferrin receptors (sTfR)* | 0.76–1.76 mg/l | 6.4–25.7 nmol/l | |
| ▶Ratio of sTfR to serum Ft (sTfR/log Ft) | <1 | ||
| Iron-deficient red cell production | |||
| ▶Haemoglobin | 12–16 g/dl (women); 13–17 g/dl (men) | ×0.6206‡ | 7.5–10 mmol/l (women); 8–10.5 mmol/l (men) |
| ▶Mean corpuscular volume | 80–100 fl | ||
| ▶Red cell distribution width | 11–15 | ||
| ▶Mean corpuscular haemoglobin | 28–35 pg | ||
| ▶Hypochromic red cells | <5% | ||
| ▶Reticulocyte haemoglobin content | 28–35 pg | ||
↵* Normal values may differ depending on the assay used.
↵† To convert the concentration values in conventional units into SI units multiply values by the conversion factor.
↵‡ In fact, although widely used, this factor allows for the calculation the molar concentration of haemoglobin subunits. Thus, the molar concentration of haemoglobin (molecular mass 64 kDa) is fourfold lower (2–3 mmol/l).