Transferrin

Transferrin levels reveal how effectively your body transports and utilizes iron. Low transferrin can indicate malnutrition, liver disease, or chronic illness, while high levels may suggest iron deficiency. Combining transferrin with iron levels helps distinguish true iron deficiency from functional deficiency, where iron is present but unavailable due to inflammation. Maintaining balanced iron intake and overall nutritional health supports proper oxygen delivery and energy metabolism.

Most adults benefit from yearly transferrin testing as part of an iron panel. After starting iron therapy, retest the full panel at 3 months.

At baseline / for screening: Once every 12 months from age 30 as part of an iron panel. More frequently, every 3 to 6 months, if you're a woman of reproductive age with heavy menstrual losses, vegetarian or vegan, or a regular blood donor.

When monitoring an intervention or change: Retest 3 months after starting or stopping iron supplementation, or after intravenous iron infusion. After blood donation or significant menstrual blood loss, allow 8 to 12 weeks for stores to begin recovering before retesting.

Note: Transferrin rises in iron deficiency and pregnancy, and falls in inflammation and chronic illness. After acute illness, wait 4 to 6 weeks before reading the value as a stable iron marker; in pregnancy, levels stay elevated until 6 to 8 weeks postpartum.