What are normal iron levels?

Normal Iron Levels

Normal serum ferritin levels are 20-250 μg/L in men and 20-200 μg/L in women, with serum iron ranging 50-175 μg/dL and transferrin saturation 20-50%. 1

Serum Ferritin Reference Ranges

Ferritin is the single most specific test for assessing iron stores in the absence of inflammation. 1

• Men: 20-250 μg/L (some sources report 24-336 μg/L) 1
• Women: 20-200 μg/L (some sources report 11-307 μg/L) 1
• Average values: 135 μg/L in men, 43 μg/L in women 1

Critical Ferritin Thresholds

• <15 μg/L: Highly specific for iron deficiency (specificity 0.99), indicating absent iron stores 1
• <30 μg/L: Generally indicative of low body iron stores and represents the lower limit of normal for most laboratories 1
• <45 μg/L: Optimal cutoff for iron deficiency in clinical practice (specificity 0.92), particularly important when chronic inflammatory processes are present 1
• >150 μg/L: Unlikely to represent absolute iron deficiency, even with concurrent inflammation 1

Important caveat: Ferritin is an acute-phase protein, so apparently normal levels may mask iron deficiency during infection, inflammation, or chronic disease (hepatitis, cirrhosis, neoplasia, arthritis). 1

Serum Iron and Transferrin Saturation

• Serum iron: 50-175 μg/dL 1
• Transferrin saturation: 20-50% (calculated as [serum iron μg/dL / transferrin] × 71.24) 1
• Transferrin saturation <20%: Indicates iron deficiency 2

Note: Serum iron and transferrin saturation are affected by inflammation and show greater day-to-day variation than ferritin, making them less reliable as standalone markers. 1

Hemoglobin Reference Ranges

The WHO defines normal hemoglobin as: 1

• Men >15 years: ≥130 g/L (13.0 g/dL)
• Non-pregnant women >15 years: ≥120 g/L (12.0 g/dL)
• Pregnant women (2nd/3rd trimester): ≥110 g/L (11.0 g/dL)

Alternative reference ranges from laboratory data: 1

• Men: 13.5-17.5 g/dL
• Women: 12.0-15.5 g/dL

Red Blood Cell Indices

• Mean Cell Volume (MCV): 80-100 fL 1
• Mean Cell Hemoglobin (MCH): Reduction indicates iron deficiency; MCH is more reliable than MCV as it's less dependent on storage conditions and is more sensitive for iron deficiency 1

Total Iron Binding Capacity (TIBC)

• Normal range: 250-370 μg/dL (45-66 μmol/L) 1
• In iron deficiency: TIBC is raised (increased capacity to bind iron) 1

Hepcidin

• Normal range: 6.7-10.4 ng/mL 1
• In iron deficiency: Decreased 1
• Advantage: More reliable indicator of iron deficiency than transferrin saturation in inflammatory conditions, though not yet widely available 1

Erythrocyte Protoporphyrin

• Adults: >30 μg/dL whole blood or >70 μg/dL red blood cells indicates iron deficiency 1
• Children 1-2 years: >80 μg/dL red blood cells indicates iron deficiency 1

Limitation: Also elevated in infection, inflammation, and lead poisoning, not just iron deficiency. 1

Clinical Context for Interpretation

When inflammation is present, standard ferritin cutoffs become unreliable because ferritin rises as an acute-phase reactant. 1 In these situations:

• Consider using higher ferritin thresholds (up to 45 μg/L) 1
• Measure additional markers: soluble transferrin receptor (0.76-1.76 mg/L), reticulocyte hemoglobin content, or hepcidin 1
• The gold standard remains bone marrow biopsy showing absent stainable iron, though this is rarely necessary 1

Age and gender variations: Post-menopausal women have much higher serum ferritin levels than menstruating women due to cessation of menstrual blood loss. 3 Children aged 6-24 months average approximately 30 μg/L. 1