Blood donation and iron reserve


What you should know...

  • Blood donations result in a loss of red blood cells and the iron they contain.
  • A significant loss of red blood cells can lead to a decrease in the capacity of the blood to transport oxygen; this is called anemia.
  • Before each blood donation, we make sure that you have enough red blood cells to give blood without any risk of becoming anemic; this is the hemoglobin test.
  • After a blood donation, the body replaces the red blood cells lost. The bone marrow regenerates these red blood cells. It takes about one month for the red blood cells to return to the level prior to the donation.
  • To manufacture new red blood cells, the bone marrow must use the iron it takes from the individual’s iron reserve. The individual must then rebuild his/her iron reserve.


How to rebuild your iron reserve?

Iron-rich diet

  • The iron needed to compensate for the losses and maintain the iron reserve at an adequate level comes from food and is absorbed by the intestine. It is therefore recommended to eat iron-rich foods
  • In the case of people making frequent blood donations (three or more whole blood donations per year for men, two or more whole blood donations for women), the iron absorbed from food may not compensate on its own for the iron lost through the donations. In most cases, donating plasma does not result in loss of iron. However, in the case of frequent plasma donors, taking the blood samples required for each donation may cause a loss of iron.

Iron supplements

  • If you donate blood frequently, it may be helpful to take iron supplements to keep your reserves up.

Talk to your physician

  • If you are a frequent donor or if you think your iron reserves are low, consult your doctor. He or she will determine if you need to be tested and take iron supplements.
  • The optimal dosage for compensating for iron losses resulting from blood donations may vary. A dosage of 18 mg elemental iron or more per day for 12 weeks following a donation may be sufficient.


Frequently asked questions

See our Sources of iron-rich foods fact sheet for some examples of iron-rich foods.

Hemoglobin is the main protein in red blood cells that carries oxygen to the tissues. It requires iron for its production. Anemia is the term used when hemoglobin in the blood is low.

Hemoglobin levels are different in women and in men.

The minimum hemoglobin level for donating whole blood is:

  • ≥ 130 g/L or 13.0 g/dL for men;
  • ≥ 125 g/L or 12.5 g/dL for women.

A test measures the amount of hemoglobin in a single drop of blood taken by a fingertip prick. Before each blood donation, we check to make sure you have enough red blood cells to donate blood without becoming anemic.

It is important to see your doctor to determine the exact cause of your low hemoglobin, especially if this is your first blood donation. Several factors can cause hemoglobin levels to be low:

  1. A technical problem during testing. Our test sometimes detects a hemoglobin level that is low but is later found to be normal when checked by the donor’s physician.
  2. Some individuals have a lower hemoglobin level than the minimum acceptable limit for donating blood, without this indicating a health issue.
  3. If you are a frequent blood donor (three or more whole blood donations per year for men, two or more whole blood donations per year for women), these donations may sufficiently decrease your iron reserve to cause anemia. If you are a frequent blood donor, it is important to mention this to your doctor. Iron supplements may be right for you. In most cases, donating by apheresis (platelets or fractionated plasma) does not cause anemia. However, in the case of frequent donors of apheresis products, taking the blood sample required for each donation and loss of red blood cells related to the procedure may cause a loss of iron.
  4. You may have bleeding which may cause your hemoglobin to drop (heavy menstrual bleeding, digestive bleeding). Depending on your symptoms, your doctor may do the necessary investigations to determine if this is the case for you.
  5. An iron-deficient diet. If this is the case, your doctor can advise you on corrective measures to take. Consult our fact sheet about iron-rich foods.
  6. Finally, other rarer factors may cause anemia. Your doctor can perform the appropriate tests to determine if this is the case.

For more information, contact our Donor Services at 1-800-847-2525.

To prevent anemia, it is important to have a good reserve of iron. Blood donors are advised to make a habit of eating more iron-rich foods.

Frequent donors (men who donate blood at least three times a year and women who donate blood at least twice a year) may need supplements to make up for the iron they lose when they donate blood. Talk to your doctor or pharmacist about whether you should take iron supplements.

To increase your hemoglobin:

  • Eat an iron-rich diet.
  • Ask your doctor or pharmacist for advice on the use of iron supplements.

Iron is essential for the human body. It is one of the components of hemoglobin. It is also found in some foods. It helps your body make new red blood cells and can help replace those lost through blood donation.

No. The test we perform on all donors before the donation measures the level of hemoglobin in the blood. To measure the iron reserve another test, called a ferritin test, is performed.

A decrease in the iron reserve can result in a sensation of fatigue, a decreased capacity for exercise, difficulties concentrating or even pica (a dietary problem characterized by the ingestion of non-nutritional substances such as ice or chalk).

A sufficiently low reserve can result in anemia, which causes the same symptoms but to a more severe degree. Anemia occurs when the hemoglobin level is less than 120 g/L in non-pregnant women and 130 g/L in men.

It is important to consult your doctor to determine the exact cause of your low hemoglobin, especially if this is your first blood donation. If you are anemic, you should refrain from donating blood until you have found the cause of your low hemoglobin and your level has returned to normal.

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