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Transferrin Saturation

Transferrin saturation in women: iron deficiency, menstruation and pregnancy

Iron, which according to the NVKC the body needs for, among other things, haemoglobin, the protein with which red blood cells bind and carry oxygen, is bound in the blood to the transport protein transferrin. The percentage of that transferrin saturated with iron is called the transferrin saturation.

According to the NVKC, transferrin saturation can establish whether there is iron deficiency or iron overload. According to the NVKC, iron deficiency can lead to anaemia, and only a blood test shows the saturation.

Diagnostiek voor U uses a transferrin saturation of 15 to 45% for women. Unilabs lists 0.06 to 0.43 for women, without a unit.

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

Female

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 %
Laboratory	Group	Reference value (%)	Relative scale
Diagnostiek voor U	· Female	15–45 %	15 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 is the percentage of transferrin that is saturated with iron, calculated from the measured iron in serum and the transferrin concentration. Diagnostiek voor U gives the calculated value as a percentage, with a separate limit for women and for men.

Transferrin Saturation: why this value matters

According to Thuisarts, blood loss from frequent long and heavy periods is the most frequent cause of anaemia in women, and according to the NVKC transferrin saturation in that form of anaemia often lies under 10%.

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: Iron Status · €89,- · Anemia · €132,-
Where: 650+ draw sites run by independent laboratories across the Netherlands. Draw sites

Transferrin Saturation: how to prepare

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.

Transferrin Saturation: when is testing worthwhile?

According to the NVKC, a doctor orders transferrin on suspicion of a shortage or an excess of iron, often in one request with the iron and ferritin tests, and transferrin saturation is calculated from the iron and transferrin together.

Transferrin Saturation: symptoms of a high or low value

Low Levels

According to the NVKC, in iron-deficiency anaemia transferrin saturation is often below 10%, and ferritin usually below 20 micrograms/l. According to Thuisarts, anaemia can show as a tired and weak feeling, the feeling of fainting, sweating and less colour in the face.

High Levels

According to the NVKC, iron overload (haemochromatosis) may be present when transferrin saturation is above 50% and iron (much) higher than 20 µmol/l. According to Thuisarts, in hereditary iron overload ever more iron can damage organs such as the liver, the pancreas, the heart and the joints.

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

See your GP with an abnormal transferrin saturation. According to Thuisarts, iron deficiency can also arise when someone eats very little iron-rich food for years on end, or from a disease that hinders the uptake of iron through the gut.

Transferrin Saturation: frequently asked questions

Does pregnancy affect iron?

According to Thuisarts, pregnancy is a situation in which the body needs more iron than comes in with food, and according to the NVKC a shortage of iron can be established with transferrin saturation.

Transferrin Saturation: sources

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
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

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