Iron Saturation levels: what's normal, high and low
The percentage of your iron-binding capacity currently being used. Iron divided by TIBC.
Medically reviewed by Youmna DiStefano, MD · Last reviewed September 2026
The short answer
Iron Saturation is measured with a standard blood draw after an 8–12 hour fast. A typical reference range is 20.0 – 50.0 %. At TestWell it's $25.99 all-in as Iron & TIBC, results in 1–3 business days, drawn at Quest or Labcorp. An out-of-range result is a prompt to look closer, not a diagnosis.
- Units
- %
- Sample
- Blood draw
- Fasting
- 8–12 hours
- Results
- 1–3 business days
- Price
- $25.99
- Labs
- Quest or Labcorp · BioReference in NY/NJ
Iron Saturation Reference Range
These are the typical adult reference ranges used by major US labs. Your report will include the specific range used by the lab that processed your sample.
| Population | Range |
|---|---|
| age 18+ | 20.0 – 50.0 % |
Reference ranges are educational. Always interpret your result with the specific range printed on your lab report and discuss anything outside the range with a clinician.
Have a result in hand? analyze it with your AI assistant using these reviewed ranges, or run it through our explainer. Tools: look up another marker's range · convert lab units
What your Iron Saturation result may mean
Can reflect iron overload (e.g. hemochromatosis) or supplement excess.
What a high Iron Saturation means: causes, symptoms, next steps ↓Often reflects iron deficiency.
What a low Iron Saturation means: causes, symptoms, next steps ↓Educational only — not a diagnosis. Many factors can influence a single result. Discuss anything that concerns you with a healthcare provider.
What does a high Iron Saturation mean?
Transferrin saturation above about 45% is the most useful screening signal for iron overload, and above 50–55% strongly suggests hereditary hemochromatosis when persistent. A recent iron supplement or meal raises it transiently, so a fasting repeat comes first. Hemolysis, liver disease and ineffective red-cell production also raise saturation.
Common causes of a high Iron Saturation
- Recent iron supplement or iron-rich meal
- Hereditary hemochromatosis
- Excess supplementation or transfusions
- Liver disease, hemolysis, some anemias with ineffective red-cell production
Ordered from most to least common.
Symptoms that can go with it
- Usually none early
- Fatigue, joint pain, liver enlargement, skin darkening, diabetes in advanced overload
What clinicians usually check next
- Fasting repeat
- Ferritin
- HFE gene testing if persistently above 45%
- Liver enzymes; family screening if positive
Follow-up tests at TestWell: Ferritin ($24.99).
What saturation suggests hemochromatosis?
Persistently above 45% (some use 50% for men, 45% for women) on a fasting sample. Genetic testing for HFE C282Y and H63D confirms it.
Educational only — not a diagnosis. A single result outside the range is a prompt to look closer with a clinician.
What does a low Iron Saturation mean?
Low transferrin saturation (below about 15–20%) indicates too little iron in circulation relative to its carrier — iron deficiency when ferritin is low, or inflammation and chronic disease sequestering iron when ferritin is normal or high. It's often the earliest abnormality in developing iron deficiency.
Common causes of a low Iron Saturation
- Iron deficiency
- Anemia of inflammation or chronic disease
- Pregnancy
- Recent menstruation, afternoon draw
Ordered from most to least common.
Symptoms that can go with it
- Fatigue, breathlessness, hair shedding if deficient
What clinicians usually check next
- Ferritin and CRP to distinguish deficiency from inflammation
- CBC
- Find the source of loss if deficient
Follow-up tests at TestWell: CBC with Differential ($21.99), Ferritin ($24.99), C-Reactive Protein (CRP) ($26.99).
Is low saturation the same as anemia?
No — it can be low well before hemoglobin drops. It's a sign iron supply isn't meeting demand.
Educational only — not a diagnosis. A single result outside the range is a prompt to look closer with a clinician.
How do you get a Iron Saturation test?
Order online, a licensed physician reviews the requisition, and you walk into a nearby lab for the draw. Iron Saturation is available on its own or inside these panels — panels cost less per marker when you want the fuller picture.
| Option | Includes | Price |
|---|---|---|
| Iron & TIBC | This marker only | $25.99 |
| Baseline Anemia Panel | 5 tests | $74.99 |
| Women's Health Panel | 8 tests | $129.99 |
| Comprehensive Anemia Workup | 8 tests | $169.99 |
| Essential Health Panel | 10 tests | $189.99 |
Quest vs. Labcorp for Iron Saturation: which lab should you pick?
Both are CLIA-certified national labs and the result is clinically equivalent, so pick whichever location is closer. Your report will print that lab's own reference range, which can differ slightly from the table above.
| Lab | Available | Price |
|---|---|---|
| Quest Diagnostics | Yes | $25.99 |
| Labcorp | Yes | $25.99 |
| BioReference (NY & NJ) | Yes | $21.99 |
Need help choosing a location? Use the lab finder to see draw sites near your ZIP.
Related Iron & Anemia biomarkers
Markers commonly tested alongside Iron Saturation.
Frequently asked
What does a high Iron Saturation mean?
Transferrin saturation above about 45% is the most useful screening signal for iron overload, and above 50–55% strongly suggests hereditary hemochromatosis when persistent. A recent iron supplement or meal raises it transiently, so a fasting repeat comes first. Hemolysis, liver disease and ineffective red-cell production also raise saturation.
What saturation suggests hemochromatosis?
Persistently above 45% (some use 50% for men, 45% for women) on a fasting sample. Genetic testing for HFE C282Y and H63D confirms it.
What does a low Iron Saturation mean?
Low transferrin saturation (below about 15–20%) indicates too little iron in circulation relative to its carrier — iron deficiency when ferritin is low, or inflammation and chronic disease sequestering iron when ferritin is normal or high. It's often the earliest abnormality in developing iron deficiency.
Is low saturation the same as anemia?
No — it can be low well before hemoglobin drops. It's a sign iron supply isn't meeting demand.
Do I need a doctor's order to test my iron saturation?
No. TestWell's licensed physician network reviews and approves your order — usually within minutes. You can place an order online without an in-person visit or a referral from your own doctor.
How long does it take to get Iron Saturation results?
Most Iron Saturation results are available in 1–3 business days after your specimen arrives at the lab. You'll get an email the moment your results are ready, with everything viewable in your TestWell portal.
How much does a Iron Saturation test cost?
Our Iron & TIBC starts at $25.99. That's the all-in price — no copays, no insurance hoops, no surprise bills. HSA and FSA cards are accepted.
Do I need to fast before my Iron Saturation test?
Yes — for the most accurate result, fast for 8–12 hours before your blood draw. Water is fine; coffee, food, and supplements are not. Your prep instructions will be included with your order.
Which lab will process my Iron Saturation test?
Your test will be processed by Quest Diagnostics, Labcorp, or BioReference depending on which is closest to you and which lab carries the test. All three are CLIA-certified and trusted by hospitals nationwide. You'll choose your lab during checkout from 4,000+ locations.
What can throw off a Iron Saturation result?
Iron supplements, recent illness and recent blood donation can change a Iron Saturation result without anything being wrong. Iron supplements can raise Iron Saturation — skip the dose that morning. Recent illness can lower Iron Saturation — wait 2 weeks. Recent blood donation can lower Iron Saturation — interpret with ferritin and the donation date. Each is explained on our physician-reviewed "Before your test" pages; when one applies, remove it and retest.
Ready to test your iron saturation?
Order in two minutes, get physician-approved, and visit a lab the same day. Starts at $25.99.