Transferrin (Iron) Saturation

The percentage of iron-binding capacity that is filled, a core iron marker.

Last reviewedJune 16, 2026

Calculated

sample type

Not applicable (calculated)

blood needed

~7 days

results in app

Morning, 7 to 10am, fasting preferred

best timing

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On this page

Why test Reference ranges What you'll learn What affects it How testing works Sources FAQ

In short

Transferrin saturation, also called iron saturation, shows how much of your iron-carrying protein transferrin is actually loaded with iron. It is a calculated value, not a separate measurement.

The formula is: transferrin saturation (%) = serum iron divided by total iron-binding capacity, multiplied by 100. It tells you the proportion of available transport capacity that is being used.

Blood Health (CBC & Iron)

Reviewed against DGKL reference practice.

Why test this?

Transferrin saturation is one of the best everyday markers of iron supply. A low value points to iron deficiency, while a high value can suggest iron overload, including conditions like haemochromatosis.

Because it combines iron and iron-binding capacity in one ratio, it gives a clearer picture of iron availability than either value alone.

What is a normal result?

Aniva reads your result against research-backed ranges, not just the lab's wide normal. The reference shown below is specific to this biomarker.

Adult reference values as used by Aniva. Ranges are guidance and can vary by laboratory and method.

Group	Normal range	Optimal range
Men	20 to 50 %	24 to 35 %
Women	15 to 50 %	24 to 35 %

Sources: Transferrin saturation 20–50% normal; <20% iron deficiency, >45–50% overload

Your Aniva report reads your result against these values together with your age, sex and the rest of your panel.

Ranges are guidance and vary by lab and assay, aligned with DGKL practice. Always read your result against your own lab's reference interval.

What insights will this test give you?

How much of your iron transport capacity is in use.
A low result that can flag iron deficiency.
A high result that can flag iron overload, read together with ferritin.

What can affect this result?

What can skew the result

Serum iron swings through the day and after meals or iron supplements, so a morning, fasting sample is preferred. Recent iron intake can falsely raise the result. Inflammation affects the components differently.

Best interpreted with

Read alongside ferritin, serum iron, and total iron-binding capacity for a full iron status picture.

How is this tested?

Sample

Calculated

Blood needed

Not applicable (calculated)

Method

Calculated

Best timing

Morning, 7 to 10am, fasting preferred

Sources. The evidence behind this

LOINC 2502-3: Iron saturation [Mass Fraction] in Serum or Plasma

Mayo Clinic Laboratories: Iron and Total Iron-Binding Capacity

WHO: Use of ferritin and related markers to assess iron status

Common questions

Which Aniva panels include this marker?

Core

Your annual full-body baseline with more than 100 biomarkers, included in your Aniva membership.

Transferrin (Iron) Saturation

Why test this?

What is a normal result?

What insights will this test give you?

What can affect this result?

What can skew the result

Best interpreted with

How is this tested?

Sources. The evidence behind this

Common questions

Which Aniva panels include this marker?

Related biomarkers usually read alongside this one

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