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Iron in Serum (Total Iron Binding Capacity, or TIBC)

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

This test measures your blood’s total capacity to carry iron, which helps assess iron status and identify potential deficiencies or overloads.

Quick summary

["Your blood’s iron-carrying ability can signal whether you’re at risk for anemia or iron overload."]

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

Key facts at a glance

LOINC
61523-7
Short code
Years iron PhenX
Synonyms
Years iron PhenX
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
Method
phenx
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

Total Iron Binding Capacity (TIBC) reflects the combined binding sites in your serum for iron, primarily carried by transferrin. It indirectly assesses iron availability and helps evaluate conditions like iron deficiency or iron overload.

How It’s Used in Diagnosis

TIBC is often ordered alongside other iron studies (e.g., serum iron, ferritin) to diagnose anemia due to iron deficiency or to monitor conditions like hemochromatosis (iron overload). Low TIBC may suggest anemia, while high TIBC can occur in chronic diseases or pregnancy.

When You Might Need This Test

Your doctor may recommend TIBC if you have symptoms of anemia (fatigue, weakness), unexplained iron deficiency, or if you’re being evaluated for conditions like hemochromatosis or chronic liver disease.

What to Expect Before the Test

No special preparation is needed. A blood sample is drawn from a vein, usually in your arm. You may feel slight discomfort, but it’s quick and painless.

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.

◆Associated findings1

Short name

TIBC

Frequently asked questions

Why might my doctor order this test?
Your doctor may check TIBC if they suspect iron deficiency (e.g., fatigue, pale skin) or iron overload (e.g., joint pain, organ damage). It’s also used in certain chronic illnesses or during pregnancy.
What do my TIBC results mean?
Results alone don’t give a full picture—your doctor will compare them with other tests (like serum iron or ferritin). Low TIBC often means your body can’t use iron well, while high TIBC may signal inflammation or pregnancy.
Can diet affect TIBC results?
Dietary iron intake (from red meat, spinach, etc.) may indirectly influence iron levels, but TIBC itself is a measure of binding capacity, not direct iron content. Avoiding heavy iron supplements for a few days before testing can help avoid interference.
  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