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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 the amount of iron in your serum to the total iron your blood can carry.

Quick summary

["Assesses iron efficiency in red blood cell production and potential iron deficiency risks."]

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

Key facts at a glance

LOINC
53503-9
Short code
Iron Spec-sCnt
Synonyms
Iron Spec-sCnt
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

Why This Test Matters

Iron saturation helps doctors diagnose conditions like iron deficiency anemia or hemochromatosis, where iron storage or use is abnormal. It’s often ordered alongside other iron studies (e.g., serum iron, TIBC) to get a full picture of your iron status.

How It’s Performed

A small blood sample is drawn from your arm. The test measures iron levels in your serum and compares them to the total iron-binding capacity (TIBC) of your blood, which reflects how much iron your blood proteins can carry.

What Results Mean

Results are typically expressed as a percentage (e.g., 20%–50% is normal). Low saturation may indicate iron deficiency, while high saturation could suggest hemochromatosis or other iron overload conditions.

Common Conditions Affecting Results

Iron saturation can be low in anemia, chronic blood loss (e.g., heavy periods, gastrointestinal bleeding), or malabsorption disorders. It may be elevated in conditions like hemochromatosis, chronic liver disease, or certain infections.

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 Ratio

Frequently asked questions

What causes might lead to abnormal iron saturation?
Abnormal results could signal underlying health issues like anemia, iron overload, or conditions affecting iron absorption. Your doctor may recommend further testing (e.g., ferritin, transferrin) to investigate.
How often should I get this test?
This test is usually ordered as part of a broader iron panel when symptoms or risk factors (e.g., fatigue, unexplained anemia) suggest iron-related problems. Follow your doctor’s guidance for follow-up.
Can diet affect iron saturation results?
Dietary iron intake (e.g., from red meat, spinach) can influence iron levels but does not directly affect the iron saturation ratio. Avoiding iron supplements or certain foods (like calcium-rich drinks) for 24 hours before testing may help stabilize 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 17, 2026. · Read our editorial policy