Transferrin Saturation 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 Saturation, which differ for men and women:

Female: Optimal 25 – 35 %; sufficient 20 – 45 %; out of range below 20 or above 45 %.
Male: Optimal 25 – 35 %; sufficient 20 – 50 %; out of range below 20 or above 50 %.

Evidence grade: Established clinical threshold. A band edge that corresponds to a recognised diagnostic, risk or treatment threshold from a major clinical guideline or public-health body.

All units

Unit	Applies to	Optimal	Sufficient	Out of range
%	Female	25 – 35	20 – 45	below 20 or above 45
%	Male	25 – 35	20 – 50	below 20 or above 50

What the evidence says

The acceptable band starts at 20%, the level below which guidelines for heart failure and kidney disease count iron as deficient, and ends where the European liver guideline starts to suspect iron overload: above 45% in women and above 50% in men and postmenopausal women. Where the client's sex is not recorded, 45% is used. Some laboratories accept down to 15% in women. The optimal band of 25 to 35% is a functional target: a Danish cohort found the lowest mortality at about 32 to 34%, but no study sets its edges. A fasting morning sample is needed, because saturation follows serum iron through the day.

Sources

EASL Clinical Practice Guidelines on haemochromatosis — European Association for the Study of the Liver — Journal of Hepatology, 2022 · Clinical guidelineProvisional iron overload is transferrin saturation above 45% with ferritin above 200 µg/L in women, and above 50% with ferritin above 300 µg/L in men and postmenopausal women. Matches Sera's upper edge of 45 for women; the men's figure is 50.
Screening, diagnosis and treatment of iron deficiency in chronic heart failure: putting the 2016 European Society of Cardiology heart failure guidelines into clinical practice — McDonagh T, Damy T, Doehner W, et al. — European Journal of Heart Failure, 2018 · Professional societyRestates the ESC heart failure definition of iron deficiency: ferritin below 100 µg/L, or ferritin 100 to 299 µg/L with transferrin saturation below 20%. Matches Sera's lower edge of 20.
Diagnosis and Management of Iron Deficiency in CKD: A Summary of the NICE Guideline Recommendations and Their Rationale — Ratcliffe LE, Thomas W, Glen J, et al. — American Journal of Kidney Diseases, 2016 · Clinical guidelineNICE guidance for chronic kidney disease: where red-cell markers are unavailable, transferrin saturation below 20% together with ferritin below 100 ng/mL identifies iron deficiency. Matches Sera's lower edge of 20.
Iron and Iron Binding Capacity | ARUP Laboratories Test Directory — ARUP Laboratories, 2026 · Laboratory / reference-interval sourceTransferrin saturation reference interval of 20 to 50%. Matches Sera's lower edge of 20 and the proposed men's upper edge of 50.
Total iron binding capacity — MedlinePlus, US National Library of Medicine, 2026 · Government / public-health guidanceNormal iron saturation is 20% to 50% in men and 15% to 45% in women. Supports sex-specific upper edges of 50 and 45; the women's lower limit of 15 is below Sera's 20.
Association of ferritin and transferrin saturation with all-cause mortality, and the effect of concurrent inflammation: a danish cohort study — Mitchell NH, Jørgensen HL, Vojdeman FJ, et al. — Scandinavian Journal of Clinical and Laboratory Investigation, 2022 · Peer-reviewed publicationIn 161,921 Danish adults both low and high transferrin saturation carried higher all-cause mortality; the lowest mortality was at 33.9% in women and 32.3% in men without inflammation. This falls inside Sera's optimal band of 25 to 35 but does not define its edges.

What Transferrin Saturation measures

The share of transferrin that is currently carrying iron.

Low saturation (<20%) points to iron deficiency even when ferritin looks normal.

Related blood cell health markers

See Transferrin Saturation in the full list of biomarker ranges

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.