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Low haemoglobin count is the most common obstacle to blood donation

9/19/2017 12:00

More and more blood donors go online or take the test at (also in English) to see if they can donate blood before coming to donate blood. Temporary reasons for deferral include the flu, surgeries and operations, tattoos and travelling in risk areas of certain diseases.

Last year, 88% of those who came to donate blood were eligible to lay down in the red cot and extend their arm. However, up to one in four new blood donors is found ineligible to donate blood on site.

According to blood donation specialist, doctor Johanna Castrén, the reasons for blood donation deferral have stayed relative unchanged in the past few years. While the internet has made donors more aware of temporary and permanent restrictions on blood donation, many are still surprised when they are asked to provide more details about their medical history especially when they come to donate blood for the first time.

“We order and analyse hundreds of patient records every year to find out if aspiring donors are eligible. For example, if we have someone who wants to donate blood and who has had cardiovascular examinations with results indicating that something is not quite right, we need to find out what this finding means in terms of the person’s eligibility to donate blood. To do this, we’ll need the patient records, and the person cannot donate blood until we’ve found more information. We do this to protect both the donor and the patient," Castrén says.

These reasons are followed by travelling in risk areas of certain diseases, a recent tattoo or piercing, recent acupuncture treatment and a new sex partner. A new sex partner and the flu are more common reasons for deferral for young people coming to donate blood for the first time compared to more regular donors.

However, low haemoglobin count is the most common reason for deferral across all age groups. For women, the minimum limit is 125 g/l, while for men it is 135 g/l.

“Sometimes donors are understandably upset if their request to donate blood is denied due to a difference of one unit. Blood donation causes the haemoglobin count to drop by 10–15 g/l, so this requirement has been laid down on the EU level in a Directive to ensure the donors’ well-being,” Castrén says.

Haemoglobin count is an individual feature, but lifestyle choices do have an impact on it. If your diet contains only a few iron-rich foods and you exercise a lot, you can easily develop iron deficiency, which causes the haemoglobin to drop. In particular young women, who are also the most relatively active blood donors, are a risk group for iron deficiency.

“The Blood Service is issuing iron tablets to those at risk of developing iron deficiency to take after the donation session. The tables should certainly be taken to replace the iron lost in the donation regardless of the haemoglobin level,” Castrén recommends.

The Blood Service is currently managing a significant FinDonor 10 000 research project to examine the impact of blood donation on iron balance.

Donors who were born or lived in a malarial area when they were under 5 years of age are never able to donate blood when they first come to donate blood as they are only tested for malaria antibodies during the first visit. The test takes a few months weeks to be completed, and if the results are negative, the person is eligible to donate blood.


1. Low haemoglobin (4.3%)
2. More information about a disease or condition required (1.1%)
3. Travelling ( in non-malaria countries) (0.9%)
4. Recent endoscopic operation, piercing or acupuncture treatment (0.9%)
5. New sex partner (0.8%)
6. Common cold (0,7 %)
7. Very low haemoglobin (0,5 %)
8. Surgical or dental procedures (0,4 %)
9. Medication (0,4 %)
10. Travel in malaria areas (0,3 %)

Take a test to find out if you are eligible to donate blood at (also in English)
Read more about the eligibility criteria to donate blood