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Serum or plasma concentration of free iron (mass concentration)

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

This test measures the amount of free (unbound) iron in your blood, which is important for assessing iron balance and identifying potential deficiencies or overloads.

Quick summary

["Free iron levels help detect iron-related health risks, such as anemia or hemochromatosis."]

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

Key facts at a glance

LOINC
33314-6
Short code
RF IgG Ser-aCnc
Synonyms
RF IgG Ser-aCnc
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
86430
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

Why This Test Matters

Iron is a vital mineral that carries oxygen in your blood. Free iron refers to the iron not bound to proteins like transferrin. Abnormal levels can indicate conditions like iron deficiency or iron overload, which may affect your energy, immune function, or risk of certain diseases.

What to Expect Before the Test

No special preparation is usually needed, but you may be asked to fast for 8–12 hours before the test if it involves a blood draw. Wear comfortable clothing and plan to stay near the testing site for a short time.

How the Test Is Performed

A healthcare provider will draw blood from a vein in your arm using a small needle. The blood sample is then sent to a lab for analysis to measure free iron concentration.

Possible Results and Their Meaning

Results are typically reported as a mass concentration (e.g., micrograms per deciliter). Low levels may suggest iron deficiency, while high levels could indicate hemochromatosis or other iron-related disorders. Your doctor will interpret the results in the context of your overall health.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Free Iron Level

Frequently asked questions

What causes free iron levels to be abnormal?
Abnormally low free iron may result from chronic blood loss (e.g., heavy periods, gastrointestinal bleeding), poor diet, or conditions like malabsorption. High free iron levels are often linked to genetic disorders (e.g., hemochromatosis), excessive iron supplements, or liver disease.
How might my doctor use this test?
Your doctor may order this test to diagnose or monitor iron-related conditions, such as anemia, hemochromatosis, or other iron metabolism disorders. It can also help guide treatment plans for conditions like thalassemia or certain infections.
Can lifestyle changes affect free iron levels?
Yes, diet plays a key role. High intake of vitamin C (which enhances iron absorption) or heme iron (from animal sources) may influence results, while certain medications (e.g., antacids) or chronic illnesses can also impact iron balance.
  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