What Is TIBC in a Blood Test?

TIBC stands for Total Iron Binding Capacity. Measures how much transferrin (iron-transport protein) is available to carry iron.

Normal Range

• 240–450 µg/dL
• High TIBC = more empty transport sites (iron deficiency)
• Low TIBC = fewer transport sites (overload or inflammation)

High TIBC Causes

• Iron deficiency — body produces more transferrin
• Pregnancy
• Oral contraceptives
• Chronic blood loss

Low TIBC Causes

• Iron overload (hemochromatosis)
• Chronic inflammation
• Liver disease
• Malnutrition
• Nephrotic syndrome

Transferrin Saturation

• (Serum Iron ÷ TIBC) × 100 = saturation percentage
• Normal: 20–50%
• Below 20% = iron deficiency
• Above 45% = hemochromatosis screening (HFE genetic testing)