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Iron Saturation Index (Serum)

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

This test measures how much of your iron is bound to a protein called transferrin, which helps carry iron in your blood. It’s important for assessing iron availability in your body.

Quick summary

["Helps identify iron deficiency or iron overload conditions by evaluating iron utilization efficiency."]

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

Key facts at a glance

LOINC
86913-1
Short code
Iron Satn goal MFr SerPl
Synonyms
Iron Satn goal MFr SerPl
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

What This Test Measures

Iron saturation reflects the percentage of transferrin’s binding sites occupied by iron. Normally, transferrin carries iron to cells that need it, like red blood cells. If saturation is low, your body may not be getting enough iron. If it’s high, it could signal iron overload or other conditions.

Why It Matters in Your Health

Low iron saturation often points to iron deficiency anemia, fatigue, weakness, or poor growth in children. High saturation may suggest hemochromatosis (iron overload) or other metabolic disorders. Your doctor may order this test if you have symptoms like unexplained fatigue, frequent infections, or unusual iron levels in other tests.

Common Reasons for Testing

Your doctor might recommend this test if you have symptoms of iron-related issues, such as anemia, unexplained fatigue, or if other blood tests (like ferritin or total iron-binding capacity) suggest iron imbalance. It’s also sometimes checked in people with chronic diseases or those who donate blood frequently.

What to Expect Before the Test

No special preparation is needed. You’ll have a small needle inserted into your arm to draw a blood sample. It usually takes a few minutes, and you can resume normal activities afterward. Avoid heavy exercise or eating a large meal before the test for best accuracy.

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

Iron Saturation

Frequently asked questions

What causes low iron saturation?
Low iron saturation can result from chronic blood loss (e.g., heavy periods, gastrointestinal bleeding), poor diet (low iron intake), malabsorption issues (e.g., celiac disease), or conditions like anemia. It may also appear in people with kidney disease or those who overuse iron supplements.
What causes high iron saturation?
High iron saturation is often linked to iron overload (hemochromatosis), excessive iron intake, or certain genetic disorders. It can also occur in people with chronic liver disease or repeated blood transfusions. Always discuss symptoms like joint pain, fatigue, or organ damage with your doctor.
How often should this test be repeated?
Your doctor will determine how often to repeat this test based on your symptoms, medical history, and other test results. If you have a known condition like hemochromatosis, follow-up may be scheduled regularly to monitor iron levels and prevent complications.
  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