Transferrin optimal range and reference range

Compiled by Alina Radu, founder of Sera, from the published sources below · Last reviewed November 9, 2026

Sera's bands for Transferrin:

  • Optimal 200 – 360 mg/dL (2 – 3.6 g/L); sufficient 170 – 370 mg/dL (1.7 – 3.7 g/L); out of range below 170 or above 370 mg/dL.

Evidence grade: Published reference interval. A band that primarily reflects a published adult laboratory or population reference interval. It is not necessarily applicable to every assay or laboratory.

All units

UnitOptimalSufficientOut of range
mg/dL200 – 360170 – 370below 170 or above 370
g/L2 – 3.61.7 – 3.7below 1.7 or above 3.7
μmol/L25.1 – 45.221.4 – 46.5below 21.4 or above 46.5

What the evidence says

Both bands are laboratory reference intervals: 200 to 360 mg/dL is the Mayo Clinic Laboratories interval, and the wider acceptable band is close to UK adult intervals of about 1.7 to 3.8 g/L. Neither is an outcome-based target. Transferrin rises in iron deficiency, in pregnancy and with oral contraceptives, and falls with inflammation, liver disease, malnutrition and protein loss, so a low value is not evidence of iron overload on its own.

Sources

  • Transferrin, Serum (Test ID TRSF) — Mayo Clinic Laboratories, 2026 · Laboratory / reference-interval sourceSerum transferrin reference values are 200 to 360 mg/dL, with no split by age or sex. This is exactly Sera's optimal band.
  • Transferrin — University Hospitals Birmingham NHS Foundation Trust, 2026 · Laboratory / reference-interval sourceAdults aged 15 to 60: 1.74 to 3.64 g/L in men and 1.80 to 3.82 g/L in women (Abbott assay). Close to Sera's sufficient band of 1.7 to 3.7 g/L.
  • Transferrin — Leeds Teaching Hospitals NHS Trust, 2026 · Laboratory / reference-interval sourceReference range 2.0 to 3.2 g/L. Supports the optimal lower edge of 2.0 g/L and shows that some laboratories use a lower ceiling than Sera's.

What Transferrin measures

The protein that carries iron through your blood.

High transferrin with low iron points to iron deficiency. Important for understanding how your body handles iron.

Related blood cell health markers

See Transferrin in the full list of biomarker ranges

About the author

Alina Radu is the founder of Sera and a software engineer. The idea started with her own Hashimoto's tests, scattered across years without the big picture. She is not a clinician: these ranges are compiled from the published sources linked on each page, with every source named. Alina Radu on LinkedIn

This page is a reference for practitioners, not medical advice. Sera's bands are practitioner targets for structured review, not diagnostic thresholds, and Sera does not diagnose or recommend treatment. Read a result alongside the interval printed by the issuing laboratory and the client's history and symptoms. Range set: Sera Production, version 1.0, last reviewed November 9, 2026.