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Iron saturation (serum iron to total iron-binding capacity ratio)

Published: August 9, 2026Updated: August 17, 2026

This test measures how well your body’s iron is being used to carry oxygen in your blood. It compares your serum iron levels to your total iron-binding capacity.

Quick summary

["Assesses iron efficiency in your blood for conditions like anemia or iron overload."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 17, 2026Editorial policy

Key facts at a glance

LOINC
2502-3
Short code
Iron Satn MFr SerPl
Synonyms
Iron Satn MFr SerPl
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
60
Ref high
170
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
83540
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

What This Test Measures

Iron saturation evaluates the percentage of your iron-binding proteins (like transferrin) that are fully loaded with iron. Low saturation may indicate iron deficiency, while high saturation could suggest iron overload or other conditions affecting iron metabolism.

Why It’s Done

Your healthcare provider may order this test if you have symptoms like fatigue, weakness, or signs of anemia (e.g., pale skin). It’s also used to monitor iron therapy or check for conditions like hemochromatosis (iron overload).

Common Reasons for Testing

Common reasons include diagnosing iron deficiency anemia, evaluating iron overload, or monitoring treatment for conditions affecting iron balance.

What to Expect Before the Test

No special preparation is needed. You’ll have a small needle inserted into your arm for a blood draw, similar to other routine blood tests. The process takes a few minutes.

Reference range

NCBI: Serum Iron Male 65-180; Female 50-170 µg/dLN/A

Specimen: serum

Fasting for 12 hours preferred. Iron supplements should be stopped 24 hours before if possible.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Iron Saturation

Frequently asked questions

How low or high results might affect your care?
Low iron saturation (below typical reference range) often points to iron deficiency, which can cause anemia and fatigue. High saturation may signal iron overload or conditions like hemochromatosis, requiring further evaluation.
What does a low result mean?
A low result suggests your body isn’t efficiently using iron, which could be due to poor diet, blood loss, or malabsorption. Your provider may recommend dietary changes, supplements, or further tests to identify the cause.
What does a high result mean?
High iron saturation may indicate excessive iron storage (e.g., hemochromatosis) or conditions like chronic liver disease. Your provider will discuss next steps, which could include blood tests, genetic screening, or lifestyle changes to manage iron levels.
  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 17, 2026. · Read our editorial policy