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Transferrin with unsaturated iron binding capacity (serum/plasma)

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

This test measures how much iron your blood protein, transferrin, can bind when it’s not already carrying iron. It helps assess your body’s ability to transport iron and can indicate iron deficiency or overload.

Quick summary

["This test helps check iron metabolism and potential blood disorders."]

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

Key facts at a glance

LOINC
89235-6
Short code
OB Transfer sum note
Synonyms
OB Transfer sum note
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
obstetrics
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 Might Be Ordered

Your healthcare provider may order this test if you have symptoms like fatigue, pale skin, or unusual tiredness, which could suggest iron deficiency. It may also be used to monitor conditions like anemia, chronic diseases, or after treatments that affect iron levels.

What to Expect Before the Test

No special preparation is needed, but you may be asked to fast for 8–12 hours before the blood draw if your test is part of a larger panel. Avoid taking iron supplements for 24 hours before the test if possible.

How the Test Works

A small sample of your blood is drawn and sent to a lab. The lab measures how much iron transferrin can bind when it’s not already carrying iron, which reflects your body’s iron-carrying capacity.

What the Results Mean

Results are compared to a reference range for your age and sex. Low values may indicate iron deficiency, while high values could suggest chronic disease or other conditions affecting iron metabolism.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: Transferrin and Iron Metabolism

Short name

UNSATURATED IRON-BINDING CAPACITY OF TRANSFERRIN

Frequently asked questions

What does a low unsaturated iron-binding capacity mean?
A low result may signal iron deficiency, where your body doesn’t have enough iron to make transferrin effectively. This can lead to anemia or other health issues if untreated.
What does a high unsaturated iron-binding capacity mean?
A high result may indicate chronic inflammation, liver disease, or other conditions that reduce iron availability for transferrin binding. It’s not always a standalone sign of iron overload.
Can diet affect this test?
Yes, iron-rich foods (like red meat, spinach, or fortified cereals) can temporarily affect iron levels in your blood. Avoiding these for 24 hours before testing may give more accurate results.
  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