Skip to content

Iron Saturation (Serum) with Transferrin

Published: August 9, 2026Updated: August 16, 2026

This test measures how well iron is bound to a protein called transferrin in your blood, which helps assess iron availability for your body’s needs.

Quick summary

["Iron saturation helps identify iron deficiency or iron overload conditions."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
75686-6
Short code
Deprecated blaIMP Bld Pos Ql Prb Mag
Synonyms
Deprecated blaIMP Bld Pos Ql Prb Mag
Category
chemistry
Sample
whole-blood
Container
Lavender-top (EDTA)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
probe-mag-capture
Specimen volume
3 mL
Stability
Room temperature: 4h, Refrigerated: 24h
Hemolysis max
0
Lipemia max
0
Icterus max
0
TAT
4–24 hours
Order
routine

What This Test Measures

Iron saturation reflects the percentage of transferrin molecules in your blood that are fully loaded with iron. Transferrin is the protein responsible for transporting iron throughout your body. When iron levels are low, transferrin binds more iron, increasing saturation. Conversely, iron overload can saturate transferrin, reducing its availability for other functions.

Why It Matters in Health

This test is important for diagnosing iron deficiency anemia (when your body lacks enough iron) or conditions like hemochromatosis (iron overload), both of which can affect energy levels, red blood cell production, and overall health.

Common Reasons for Testing

Your doctor may order this test if you have symptoms like fatigue, pale skin, weakness, or if you have a history of blood loss, frequent infections, or unexplained anemia.

Sample Collection and Preparation

A blood sample is drawn from a vein in your arm. The test measures iron binding capacity in serum (liquid part of blood after clotting). No special preparation is needed, but fasting may be advised depending on other tests ordered together.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Iron Binding Capacity

Frequently asked questions

How does iron saturation differ from total iron levels?
Iron saturation is a ratio that shows how efficiently your body uses transferrin to carry iron. While total iron levels measure absolute iron amounts, saturation helps determine if iron is being properly utilized or stored in your body.
What might cause low iron saturation?
Low iron saturation often indicates iron deficiency, which can stem from chronic blood loss (e.g., heavy periods, gastrointestinal bleeding), poor diet, or malabsorption issues. It may also signal conditions like anemia or certain medications affecting iron absorption.
Can iron saturation be affected by medications?
Yes, some medications (e.g., antacids, proton pump inhibitors) can interfere with iron absorption, potentially lowering saturation. Always inform your doctor about all medications you take.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy