Insight into your iron level.
Serum iron is the amount of iron circulating in your blood at the moment of the blood draw. A test gives insight into that circulating iron, as part of the broader picture of your iron status.
Also known as: serum iron, Fe
Interpreted by BIG-registered doctors
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Background
What is iron?
Iron is a mineral the body needs to make haemoglobin, the protein in red blood cells that carries oxygen around the body. Iron also plays a role in energy metabolism within the cell and in the function of various enzymes. Serum iron is the portion of iron circulating in the blood at that moment, bound to the transport protein transferrin.
The difference from ferritin matters. Ferritin reflects the iron stores in the body and is therefore more stable. Serum iron, by contrast, fluctuates considerably: the value changes over the course of the day and rises after a meal or after taking an iron supplement. For assessing iron status, ferritin is therefore usually more informative. Serum iron mainly adds supplementary information, certainly in combination with ferritin and with markers such as transferrin.
In brief
Oxygen transport
Building block of haemoglobin in red blood cells
Snapshot
Fluctuates over the day and after a meal
Ferritin is the store
Serum iron is the circulating part
Transport
Bound to transferrin in the blood
Common reasons to test
When can insight into your Iron be valuable?
Below are some situations in which measuring Iron can provide insight.
Insight into your iron status
A test gives a snapshot of the iron circulating in your blood, as a complement to ferritin.
Together with ferritin
Ferritin shows the iron stores, serum iron the circulating iron. Together they give a fuller picture of your iron status.
With persistent fatigue
Fatigue is a complaint for which people often have their iron status checked. Iron is then best viewed together with ferritin.
For athletes
Intensive endurance training can increase iron requirements. Athletes therefore often include iron in their periodic check.
With blood loss or donation
Heavy menstruation or regular blood donation increases iron loss. A test gives insight into your current value.
Tracking the effect of supplementation
Those taking iron supplements can track the effect. Do not take the supplement on the morning of the draw, as this temporarily raises serum iron.
What your result means
How do we read your Iron level?
Serum iron is measured in micromoles per litre (µmol/L). The laboratory states the reference values that apply there alongside your result. Important: serum iron fluctuates considerably over the day and after a meal or supplement. A single measurement is therefore a snapshot and says little on its own about your iron stores.
A low value
A low serum iron may fit with an iron deficiency, for example due to insufficient intake, reduced absorption from the gut, or blood loss. Because the value fluctuates so much, a low serum iron on its own is not enough to establish an iron deficiency. Ferritin is more informative for that. Our doctor provides explanation and indicates whether further investigation is customary.
A normal value
A serum iron within the laboratory's reference values gives a reassuring picture for this marker at this moment. It remains a snapshot. A normal value does not rule out low iron stores, because serum iron can be normal while the stores have already decreased. Ferritin gives additional insight into that.
An elevated value
An elevated serum iron is often explained by an iron supplement taken recently or an iron-rich meal before the draw. If the value remains elevated, this may point to increased iron accumulation in the body. A single measurement is not a diagnosis. Our doctor explains what your value means and whether a repeat test or follow-up via your GP is customary.
How we interpret your result
Our doctors interpret your iron level against the laboratory's reference values and your personal context, such as lifestyle, diet, supplements, medication use and any known conditions.
Related tests
Often combined with Iron.
A single marker gives one perspective. For a broader picture you can combine Iron with a theme package or related markers.
Frequently asked questions
Everything you want to know
Do I need to fast for an iron test?
Fasting is not strictly required, but it is advisable. Serum iron rises after a meal and certainly after an iron supplement. A morning measurement, before breakfast, is the most comparable with a later measurement.
What is the difference between iron and ferritin?
Ferritin reflects the iron stores in your body and is a stable measure of your iron status. Serum iron is the iron circulating in your blood at that moment and fluctuates considerably over the day. For assessing iron status, ferritin is therefore usually more informative.
Does a normal serum iron mean I do not have an iron deficiency?
Not with certainty. Serum iron can be normal while the iron stores have already decreased. If you want to know how your stores are doing, ferritin is the marker of choice, preferably assessed together with serum iron.
Does my iron supplement affect the result?
Yes, and this is a common mistake. An iron supplement taken shortly before the draw raises serum iron temporarily and substantially. Do not take the supplement on the morning of your blood draw, and mention during your intake that you use it.
What time of day is best for the test?
In the morning. Serum iron follows a daily rhythm and is generally different later in the day than in the morning. If you test repeatedly, always test at roughly the same time so your values are comparable.
Which foods contain a lot of iron?
Red meat, liver, legumes, tofu, nuts, seeds, wholegrains and leafy green vegetables are well-known sources. Iron from plant sources is less easily absorbed. Vitamin C with a meal supports absorption, while coffee and tea inhibit it.
How often should I have iron measured?
A single measurement is enough for initial insight, preferably together with ferritin. If you take iron supplements or an earlier value was abnormal, re-testing after a few months is customary. Your doctor will advise on this.
What do I do with my result?
You receive a PDF report with your value and a personal explanation from our doctor. What you do with it, such as discussing it with your GP, remains entirely your choice.
Ready for insight into your iron level?
For €49 you receive your iron level including personal explanation from a doctor, typically within a few working days. No referral required.
Order Iron for €49 →Want to test multiple markers at once?
Combine Iron with other markers via Bloodworks Select. Blood draw costs are waived from €225.
49,-
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