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Minerals

Transferrin saturation: what percentage of transferrin is saturated with iron

Transferrin is the protein that carries iron through the blood: according to the NVKC, the Dutch society of clinical chemists, iron does not occur in free form in the blood but is bound to transferrin, which has two places per molecule to bind iron. According to the NVKC, the body needs iron for, among other things, making haemoglobin, the protein with which red blood cells bind and carry oxygen. According to the NVKC, transferrin saturation shows what percentage of transferrin is saturated with iron.

According to the NVKC, transferrin saturation can establish whether there is iron deficiency, for example from chronic blood loss, a poor diet or poor gut function, or iron overload (haemochromatosis), a condition in which too much iron is stored in the body. According to Thuisarts, the Dutch GPs' patient site, people with hereditary iron overload often notice little or nothing of it. Only a blood test shows transferrin saturation.

Diagnostiek voor U uses 15 to 45% for transferrin saturation in women and 20 to 45% in men. Unilabs gives the saturation without a unit, as 0.12 to 0.43 in men and 0.06 to 0.43 in women.

Doctor's Assessment Included

Transferrin saturation shows what percentage of the iron transport protein transferrin is saturated with iron. According to the NVKC, the saturation usually lies between 20% and 45%, and it helps establish whether there is iron deficiency or iron overload.

  • Diagnostiek voor U uses 15 to 45% in women and 20 to 45% in men; Unilabs gives 0.06 to 0.43 in women and 0.12 to 0.43 in men, without a unit.
  • According to the NVKC, in iron-deficiency anaemia transferrin saturation is often below 10%.
  • According to the NVKC, a transferrin saturation above 50%, with iron (much) higher than 20 µmol/l, can point to iron overload.

Reference Ranges

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Choose male or female — this range differs by sex.

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

Male Your group
%
Low 20 Normal 45 High
Female Your group
%
Low 20 Normal 45 High

Source: NVKC Reference population: Dutch adults (NVKC)

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

Transferrin Saturation: what Dutch laboratories use

Reference ranges by group, in %
Diagnostiek voor U · Female 15–45 %
15 45
Diagnostiek voor U · Male 20–45 %
20 45
0 49.5 %

Source: Diagnostiek voor U

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

Transferrin Saturation: what this test measures

Transferrin saturation gives, as a percentage, how much of the transferrin is saturated with iron, calculated according to the NVKC from the measured amount of iron in serum and the transferrin concentration. Unilabs and Diagnostiek voor U both state that the saturation is a calculation, and Unilabs expresses the outcome without a unit. The NHG, the Dutch college of general practitioners, describes the iron saturation percentage as the ratio between iron and transferrin or the total iron-binding capacity (TIBC).

Transferrin Saturation: why this value matters

According to the NVKC, transferrin saturation helps establish whether there is iron deficiency or iron overload. The iron saturation percentage, as the NHG calls transferrin saturation, is according to the NHG lowered in iron-deficiency anaemia, because iron is lowered and the total iron-binding capacity (TIBC) raised, and less lowered or normal in anaemia of chronic disease. According to Thuisarts, in hereditary iron overload ever more iron can damage organs, for example the liver, the pancreas, the heart and the joints.

Transferrin Saturation: 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 & mineral checkup · €229,-
Where
650+ draw sites run by independent laboratories across the Netherlands. Draw sites

Transferrin Saturation: how to prepare

  1. 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.

  2. 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.

Transferrin Saturation: when is testing worthwhile?

Transferrin saturation is calculated from iron and transferrin, and according to the NVKC a doctor requests transferrin when an excess or a shortage of iron in the body is suspected, often together with the iron test and the ferritin test. According to the NVKC, with symptoms of iron overload such as tiredness, joint complaints or diabetes, blood tests for iron can establish whether the hereditary form is present.

Transferrin Saturation: symptoms of a high or low value

Low Levels

According to the NVKC, a low transferrin saturation is common, for example in women who lose too much blood during menstruation, so that iron deficiency develops that can lead to anaemia. According to the NVKC, in this iron-deficiency anaemia the saturation is often below 10% and ferritin usually below 20 micrograms/l. According to Thuisarts, anaemia can show as a tired and weak feeling, dizziness, headache, the feeling of not getting enough air when climbing stairs or exercising, and less colour in the face.

High Levels

According to the NVKC, with a raised result iron is (much) higher than 20 µmol/l and transferrin saturation higher than 50%, and there may then be iron overload, a disease in which the body constantly absorbs too much iron from food in the gut. According to the NVKC, ferritin is then usually strongly raised too, above 500 micrograms/l. According to Thuisarts, hereditary iron overload may only become noticeable once there is a lot of iron in the body, usually between the ages of 40 and 50. According to Thuisarts, possible symptoms of hereditary iron overload are tiredness, pain in the joints, usually in the hands and wrists, abdominal pain, a greyish-brown skin, heart complaints and, in men, erectile dysfunction, and according to Thuisarts these symptoms can also have another cause.

Transferrin Saturation: causes of a low or high value

What lowers the value

  • Iron deficiency from blood loss

    Chronic blood loss can lead to iron deficiency, and women can lose too much blood during menstruation; in the iron-deficiency anaemia that can result, transferrin saturation is often below 10%.

  • Iron deficiency from diet or gut function

    A poor diet or poor gut function can lead to iron deficiency, and transferrin saturation helps establish that deficiency.

What raises the value

  • Iron overload (haemochromatosis)

    With iron (much) higher than 20 µmol/l and a transferrin saturation above 50%, there may be iron overload, in which the body constantly absorbs too much iron from food in the gut.

  • Having just started iron tablets

    A raised result for iron and transferrin saturation can also occur in people who have just started taking iron tablets.

Transferrin Saturation: lifestyle and this value

Discuss an abnormal transferrin saturation with your GP. According to Thuisarts, when the doctor thinks someone has hereditary iron overload, a DNA test in hospital follows, and according to Thuisarts the treatment is usually bloodletting, in which half a litre of blood is taken each time. Thuisarts advises people with hereditary iron overload to eat no or little red meat, to take no fruit or fruit juice with vitamin C at meals, to drink no alcohol and to take no medicines or supplements containing iron, such as multivitamins.

Transferrin Saturation: frequently asked questions

Is transferrin saturation the same as ferritin?

No, transferrin saturation and ferritin measure different things. According to the NVKC, the saturation shows what percentage of the transport protein transferrin is saturated with iron, while according to the NVKC ferritin is the protein in which the body stores its iron reserve in the cells of the liver.

When is blood for a transferrin saturation preferably taken?

According to the NVKC, the blood draw for iron, from which transferrin saturation is calculated, is preferably done in the morning before breakfast, because iron-rich food such as apple syrup or spinach temporarily raises iron.

Can a raised transferrin saturation come from iron tablets?

Yes, according to the NVKC a raised result for iron and transferrin saturation can also occur in people who have just started taking iron tablets.

Transferrin Saturation: sources

  1. Nederlandse Vereniging voor Klinische Chemie en Laboratoriumgeneeskunde. Alles over testen. Over AFP: "De referentiewaarden kunnen verschillen tussen laboratoria, afhankelijk van de methode. Ga daarom uitsluitend af op de referentiewaarden van het laboratorium dat het onderzoek heeft uitgevoerd en interpreteer nooit AFP-uitslagen van verschillende laboratoria door elkaar." Geraadpleegd 14 juli 2026. (retrieved 2026) allesovertesten.nl
  2. Diagnostiek voor U, eLabgids (Referentiewaarden DvU), diagnostiek.getincontrol.eu, geraadpleegd 2026-10-01 (retrieved 2026) diagnostiek.getincontrol.eu
  3. NVKC, Alles over testen: IJzer, allesovertesten.nl, geraadpleegd 2026-10-16 (retrieved 2026) allesovertesten.nl

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