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Iron (Serum)

Iron in your blood: what you eat, what reduces uptake and what a low or high value means

Your body gets iron from food: your gut takes it up, the transport protein transferrin carries it through your blood, and most of it ends up in haemoglobin, the protein that carries oxygen through your blood.

Years of eating very little iron can lead to too little iron in the body according to Thuisarts, and in hereditary iron overload the gut instead constantly takes up too much iron from food, the NVKC writes. Only a blood test shows whether there is too little or too much iron in your blood.

Iron is measured in micromoles per litre (µmol/l). Certe uses 10 to 30 µmol/l for everyone and calls that target values.

Doctor's Assessment Included

Serum iron is the amount of iron in the blood at the moment of the draw; in healthy people it averages about 20 µmol/l according to the NVKC. Star-SHL and Unilabs use separate limits for men and women, Star-SHL also per age, and Certe one limit for everyone.

The NVKC advises drawing blood preferably in the morning before breakfast, because iron-rich food raises iron temporarily.
According to the NVKC, iron is preferably judged with the transferrin saturation, which usually lies between 20% and 45%; with an iron (much) higher than 20 µmol/l and a saturation above 50%, there can be iron overload.
Certe uses one iron limit of 10 to 30 µmol/l for all ages and both sexes, and calls it target values.

Reference Ranges

See the value that applies to you:

Age years

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This range also depends on context such as cycle phase or sample material; the highlighted rows apply to your group.

Your reference range

umol/l

6 39 umol/l

Reference ranges by group, in umol/l
Sex	Age	Reference range (umol/l)	Relative scale
Male	· 6–12 years	7–30 umol/l	7 30
Male	· 13–18 years	9–35 umol/l	9 35
Male	· 19–50 years	8–39 umol/l	8 39
Male	· 51–65 years	8–35 umol/l	8 35
Male	· 66–80 years	7–31 umol/l	7 31
Male	· 81 years and older	8–29 umol/l	8 29
Female	· 6–12 years	7–31 umol/l	7 31
Female	· 13–18 years	6–35 umol/l	6 35
Female	· 19–50 years	7–35 umol/l	7 35
Female	· 51–65 years	8–30 umol/l	8 30
Female	· 66–80 years	8–30 umol/l	8 30
Female	· 81 years and older	7–28 umol/l	7 28

6 39 umol/l

Source: NVKC Reference population: Dutch general-practice population (NUMBER, n = 7,574,327)

Reference ranges may vary between laboratories. When you order a test, a BIG-registered doctor assesses your personal results in context. For treatment decisions, discuss your results with your GP.

Check your own value

Iron (Serum): what Dutch laboratories use

Reference ranges by group, in umol/l
Laboratory	Group	Reference value (umol/l)	Relative scale
Star-shl	· Male · 19–50 years	8–39 µmol/l	8 39
Star-shl	· Female · 19–50 years	7–35 µmol/l	7 35
Star-shl	· Male · 51–65 years	8–35 µmol/l	8 35
Star-shl	· Female · 51–65 years	8–30 µmol/l	8 30
Star-shl	· Male · 66–80 years	7–31 µmol/l	7 31
Star-shl	· Female · 66–80 years	8–30 µmol/l	8 30
Star-shl	· Male · 81 years and older	8–29 µmol/l	8 29
Star-shl	· Female · 81 years and older	7–28 µmol/l	7 28
Unilabs	· Male	14–35 µmol/l	14 35
Unilabs	· Female	10–25 µmol/l	10 25
Certe	· Everyone · target values	10–30 umol/L	10 30
Diagnostiek voor U	· Male	14–35 µmol/L	14 35
Diagnostiek voor U	· Female	10–25 µmol/L	10 25

0 42.9 umol/l

Source: Star-shl

Source: Unilabs

Source: Certe

Source: Diagnostiek voor U

Each value as the laboratory itself publishes it, retrieved in 2026.

Iron (Serum): what this test measures

Certe measures iron in lithium heparin plasma and reports it in micromoles per litre (µmol/l): the amount of iron in your blood plasma at the draw. How recently you took in iron can change the result according to MedlinePlus, and according to the NVKC iron-rich food such as apple syrup or spinach raises iron temporarily.

Iron (Serum): why this value matters

Serum iron matters because a low iron can end in anaemia, which according to Thuisarts usually comes from too little iron in the body.

Too much iron can also harm: in hereditary iron overload, according to Thuisarts, iron that keeps building up can damage organs such as the liver and the pancreas.

Iron (Serum): how the blood test works

Referral: No GP referral needed. After the order we arrange the referral through ZorgDomein, within one business day; orders after 17:00 or at the weekend start on the next business day. ZorgDomein emails a barcode, and that barcode is what the draw site needs.
The draw: A blood draw from a vein in the arm, at a partner laboratory's draw site. No home kit, no finger prick.
Which test: Vitamin and Iron Panel · €104,- · Blood Test Iron, Vitamins · €149,-
Where: 650+ draw sites run by independent laboratories across the Netherlands. Draw sites

Iron (Serum): how to prepare

Better not right after an infection
Recommended

After an infection or vaccination this value can be off for 2 weeks. Preferably draw once you are fully recovered.
Preferably fasting
Recommended

Coming fasting gives a slightly cleaner value, but it is not required. If it suits you, eat nothing from 22:00 the evening before and drink only water.
Preferably in the morning
Recommended

A morning draw makes this value easiest to compare with its reference range. Plan the draw before 10:00 if you can.

Water is always fine. Drink as usual beforehand, it makes the draw easier.
Take your usual medication, unless your own doctor told you otherwise.

Iron (Serum): when is testing worthwhile?

According to the NVKC, an iron measurement is meant to detect iron deficiency or, the other way round, iron overload, and according to the NVKC the blood is preferably drawn before breakfast.

Iron (Serum): symptoms of a high or low value

Low Levels

A low iron from years of eating very little iron or poor uptake in the gut can cause anaemia according to Thuisarts, with symptoms such as shortness of breath on stairs, dizziness and a tired feeling.

According to MedlinePlus, a lower iron may be a sign of, among other things, intestinal conditions that disturb iron uptake, or of too little iron in the diet.

High Levels

Hereditary iron overload, in which according to Thuisarts more and more iron enters the body very slowly, can cause a grey-brown skin, abdominal pain or heart rhythm disorders, among others, usually only once a person is between 40 and 50. Thuisarts writes that people with hereditary iron overload often notice nothing or little of it and that those symptoms can also have another cause. MedlinePlus lists a higher-than-normal serum iron as a possible sign of, among other things, too much iron in the body (haemochromatosis), anaemia from red blood cells being destroyed too quickly (haemolytic anaemia) or liver tissue death. According to the NVKC, iron overload may be at play when an iron (much) higher than 20 µmol/l goes together with a transferrin saturation above 50%.

Iron (Serum): causes of a low or high value

What lowers the value

Heavy periods

According to the NVKC, women can lose so much blood during their period that iron deficiency develops, and that can lead to anaemia.
Long-term blood loss through the stomach or bowel

According to Thuisarts, losing small amounts of blood through the stomach or bowel over a long time is often the cause of too little iron in people over 50.
Too little iron in the diet

According to Thuisarts, years of eating very little food that contains iron can lead to too little iron in the body.
Poor uptake in the gut

According to Thuisarts, the body can have too little iron with a disease that makes it harder for iron to get into the body through the gut.
Pregnancy

According to Thuisarts, the body needs more iron during pregnancy than comes in with food.

What raises the value

Hereditary iron overload (haemochromatosis)

With an iron (much) higher than 20 µmol/l and a transferrin saturation above 50%, there can be iron overload according to the NVKC, in which the body constantly takes up too much iron from food.
Recently started iron tablets

According to the NVKC, a rise can also occur in people who have just started taking iron tablets.
Iron-rich meal before the draw

Iron-rich food, such as apple syrup or spinach, gives a temporary rise according to the NVKC; that is why blood is preferably drawn in the morning before breakfast.
Inflammation of the liver (hepatitis)

According to MedlinePlus, a higher-than-normal iron may be a sign of inflammation of the liver.
Frequent blood transfusions

According to MedlinePlus, a higher-than-normal iron may be a sign of frequent blood transfusions.

Iron (Serum): lifestyle and this value

Iron-rich food, such as apple syrup or spinach, raises the iron in your blood temporarily according to the NVKC, and according to Thuisarts red meat contains a lot of iron. In hereditary iron overload, Thuisarts instead advises no or little red meat and no fruit or fruit juice with vitamin C at meals, because vitamin C makes the body take up more iron from food.

Iron (Serum): frequently asked questions

Do coffee and tea reduce iron uptake?

According to Thuisarts, coffee, tea and milk make iron get into your body less well; that is why Thuisarts advises taking an iron pill only 4 hours after such a drink.

Why is iron drawn before breakfast?

According to the NVKC, iron is preferably drawn in the morning before breakfast, because iron-rich food such as apple syrup or spinach raises the value temporarily.

Does vitamin C help iron uptake?

According to Thuisarts, vitamin C makes more iron get into your body, which is why Thuisarts advises an orange or kiwi with the iron pill.

Iron (Serum): sources

den Elzen WPJ, Brouwer N, Thelen MH, Le Cessie S, Haagen I-A, Cobbaert CM. NUMBER: standardized reference intervals in the Netherlands using a 'big data' approach. Clin Chem Lab Med 2018;57(1):42-56. (retrieved 2026) doi.org
Star-shl, Labbepalingen (referentiewaarden per bepaling), star-shl.nl, geraadpleegd 2026-10-01 (retrieved 2026) star-shl.nl
Unilabs, Bepalingenklapper (referentiewaarden per bepaling), bepalingenklapper.nl, geraadpleegd 2026-10-01 (retrieved 2026) bepalingenklapper.nl
Certe, Bepalingenwijzer (referentiewaarden per bepaling), bepalingenwijzer.certe.nl, geraadpleegd 2026-10-01 (retrieved 2026) bepalingenwijzer.certe.nl
Diagnostiek voor U, eLabgids (Referentiewaarden DvU), diagnostiek.getincontrol.eu, geraadpleegd 2026-10-01 (retrieved 2026) diagnostiek.getincontrol.eu
NVKC, Alles over testen: IJzer, allesovertesten.nl, geraadpleegd 2026-10-16 (retrieved 2026) allesovertesten.nl
NHG, Thuisarts.nl: Ik heb bloedarmoede, geraadpleegd 2026-10-12 (retrieved 2026) thuisarts.nl
MedlinePlus Medical Encyclopedia: Serum iron test, U.S. National Library of Medicine, geraadpleegd 2026-10-12 (retrieved 2026) medlineplus.gov

Test Products

This marker is included in the following test panels.

Vitamins

Vitamin and Iron Panel

Iron status (ferritin, iron, transferrin) and vitamin D — eating a lot less also means taking in fewer nutrients.

Iron (Serum) Transferrin Saturation Vitamin D (25-OH) Ferritin Transferrin

€104,-

Vitamins

Blood Test Iron, Vitamins

Complete blood count, iron status, vitamin B12 and vitamin D in one panel — eating a lot less also means fewer nutrients coming in.

Iron (Serum) Transferrin Saturation Vitamin B12 Vitamin D (25-OH) Ferritin Transferrin Basic Blood Count

€149,-

Medical standards

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Medical policy

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