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Hemoglobin Free Iron in Plasma (Mass Concentration)

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

This test measures the amount of free (unbound) iron present in your plasma, which can help assess iron metabolism and certain blood disorders.

Quick summary

["Free iron levels may indicate iron overload risks or deficiencies in your body."]

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

Key facts at a glance

LOINC
109623-9
Short code
Hgb Free Msmt Plas
Synonyms
Hgb Free Msmt Plas
Category
hematology
Sample
plasma
Container
Lavender-top (EDTA) or Green-top (Heparin)
Units
N/A
Ref low
12
Ref high
17.5
Critical range
7 N/A – 20 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
85018
SNOMED
900000000000003004
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 Does This Test Measure?

The test specifically looks at free iron—iron that is not bound to proteins like transferrin. This form of iron can be important for diagnosing conditions related to iron storage or utilization, such as hemochromatosis or iron deficiency.

Why Might You Need This Test?

Your healthcare provider may order this test if you have symptoms like fatigue, weakness, or if you have a history of iron-related disorders. It may also be used in research or specialized clinical settings to monitor iron dynamics.

How Is the Test Performed?

A blood sample is drawn from a vein, usually in your arm. The plasma portion is then analyzed using a specialized method to measure free iron concentration.

What Are Common Uses?

This test is less commonly used in routine clinical practice but may be part of broader evaluations for iron overload syndromes, genetic testing, or research studies involving iron metabolism.

Reference range

Adult males: 13.5-17.5 g/dL; Females: 12.0-16.0 g/dLN/A

Specimen: plasma

No special preparation usually required. Stay well hydrated. Inform your healthcare provider of all medications and supplements you are taking.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Free Iron in Plasma

Frequently asked questions

Why do some people need to know their free iron levels?
Free iron levels can be elevated in conditions like hemochromatosis (iron overload) or may be low in iron deficiency. Monitoring free iron helps guide treatment and prevent complications like organ damage from excess iron.
How does free iron differ from total iron in blood tests?
Free iron is the unbound form of iron in plasma, separate from iron bound to proteins like transferrin. Measuring free iron can provide additional insight into iron availability for cells compared to total iron alone.
Can diet affect free iron levels?
Dietary iron intake (from foods like red meat, spinach, or fortified cereals) can influence overall iron status, but free iron levels specifically are primarily assessed through blood tests and may not be directly affected by diet alone.
  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