Iron
Serum iron — the amount of iron circulating in the blood right now. Best interpreted with ferritin and transferrin, as it varies through the day.
Typical reference range
| Range | Unit |
|---|---|
| 11–31 (male) | umol/l |
| 9–30 (female) | umol/l |
What Iron measures
Serum iron measures the amount of iron circulating in your blood, most of it bound to a transport protein called transferrin. It reflects iron in transit rather than the iron your body has stored away.
A single serum iron value is a snapshot that can shift quite a bit over the course of a day. It rises and falls with your diet, the time of blood draw, and any recent iron supplements or high-iron meals. Because of this fluctuation, it is rarely interpreted on its own.
Instead, clinicians read it as part of the iron studies panel, alongside ferritin (a marker of iron stores), transferrin or TIBC, and transferrin saturation. Together these give a fuller picture than any one number.
What a high Iron can mean
A higher-than-expected serum iron value can have several explanations, and many of them are harmless and short-lived.
- Recent iron supplements or a high-iron meal before the blood draw are among the most common reasons for a single elevated reading.
- Repeated blood transfusions, which introduce extra iron over time.
- Iron overload conditions such as hereditary hemochromatosis, which is usually read together with a high transferrin saturation and elevated ferritin rather than serum iron alone.
- Certain liver conditions can also be associated with altered iron levels.
Because diet and supplements so often explain an isolated high value, a single result is best understood alongside the fuller iron panel. If your iron studies are consistently high, it is worth discussing them with a clinician, who can look at the pattern across markers and your history before drawing any conclusions.
What a low Iron can mean
A lower-than-expected serum iron value is commonly associated with the body having less iron available, though it can arise for different reasons.
- Iron deficiency is a frequent cause, which may stem from blood loss, low dietary intake, poor absorption, or increased demand during pregnancy. This is often seen alongside low ferritin and low transferrin saturation.
- Inflammation can also temporarily lower serum iron even when stores are adequate, which is one reason the marker is not read in isolation.
When iron is genuinely low, people sometimes notice symptoms such as fatigue, weakness, or pallor, though these are non-specific. Because a low value can reflect either true deficiency or a temporary shift, interpretation depends on the whole iron panel together with your symptoms and history. A clinician can weigh these factors and advise on any next steps.
Track your Iron over time in Quanome — it reads your lab reports (PDF or photo) on your device, charts each marker against its range, and an AI coach explains what your trends mean alongside your Apple Health and DNA.