Haemoglobin and iron

Every time you come to give blood, plasma or platelets we check your haemoglobin level.

Haemoglobin, or 'Hb', is a protein found in the red blood cells that carries oxygen around your body and gives blood its red colour.

Haemoglobin levels vary from person to person. Men usually have higher levels than women.

We set a fairly high 'cut-off' level because we want to be sure that your haemoglobin will not drop below normal after you have donated.

To ensure your safety we need your Hb to be at least 125g/l for women and 135g/l for men prior to donation.

If you donate platelets you also lose a certain number of red cells each time, and after a number of donations your iron stores and Hb can drop, so we still need to check you Hb levels before donation.

Why haemoglobin levels might be too low to donate

There are three common reasons:

  • Variation between people – some of us just normally have a lower level than others.
  • Iron – we all need iron to make haemoglobin. If your iron stores are low, the haemoglobin may fall below normal (or below the donation level).
  • Testing procedure – while we take great care with our test on the session, occasionally it underestimates the amount of haemoglobin in the blood.

At your next donation

You will have been asked to leave at least 3 months before your next donation to allow your haemoglobin to reach a higher level. We hope that next time you come to give blood your haemoglobin will be above our ‘cut-off’ level and that you will not be disappointed again.

If you are unable to donate on 3 consecutive occasions then you will be withdrawn as a donor.

More about iron

Iron is very important because it helps your body to make haemoglobin. You give away a lot of iron when you donate blood.

As iron is found in a variety of foods, you can usually get enough from a balanced diet. In the UK, the major sources of iron are meat and meat-based foods, cereals and vegetables.

Boosting iron levels

You can boost iron levels by trying to eat a well-balanced diet.

Although iron from non-meat sources is more difficult for the body to absorb, people following a well-balanced vegetarian or vegan diet should get enough iron in their diet.

Every day, try to eat three portions of food in this list which are good sources of iron:

  • lean red meat, turkey and chicken
  • fish - including mackerel, sardines, salmon, pilchards and shellfish
  • eggs
  • breakfast cereals - some cereals are fortified with iron
  • pulses and beans - in particular baked beans, chickpeas and lentils
  • nuts (including peanut butter)
  • brown rice
  • tofu
  • bread - especially wholemeal or brown breads
  • leafy green vegetables – especially curly kale, watercress, broccoli and spinach
  • dried fruit - in particular apricots, raisins and prunes

Vitamin C

Vitamin C helps you to absorb more iron. To get the most from the food you eat, have vitamin C rich foods with meals, for example fresh fruits and vegetables, or drinks such as fresh orange juice.

Avoid drinking tea just before, after or with meals as this may reduce the absorption of iron from foods.

Further information

If you are worried or require further information call our donor helpline on 0300 123 23 23.