Can Someone's Blood Type Change, and What Happens to Their Donated Blood?

Do you wonder if a person's blood type can change? Typically, blood type remains stable throughout a person's life, but certain medical interventions can alter it. This article explores the conditions under which blood type changes, the implications for donated blood, and the science behind blood type.

Why Blood Type Can Change: Bone Marrow Transplants

bone marrow transplants (BMT) are the only known instances where a person's blood type might change. Specifically, when a patient undergoes a BMT, their bone marrow is destroyed and replaced with marrow from a donor. This procedure can lead to a change in the recipient's blood type. Here’s how it works:

A friend of mine had a rare form of leukemia and required a bone marrow transplant. The doctors killed off his bone marrow, meaning he no longer produced any blood. Transfusions sustained his life until the doctor's bone marrow was replaced with donor tissue.

Interestingly, in this case, the donor had a different blood type from my friend. The recipient's blood type effectively “changed” to match the donor's. This scenario highlights the extraordinary nature of bone marrow transplants and their profound impact on the human body.

Is This a Common Occurrence?

While rare, this case is not entirely unheard of. There have been instances where patients have been discovered to have blood types that they had previously assumed were different. For example:

In one such case, a patient undergoing a bone marrow transplant for cancer had their blood type change to match the donor's. This underscored the transformative power of BMT, where the recipient's existing bone marrow is completely replaced, leading to a change in blood type.

Another instance involves a patient whose original blood type was thought to be one type, but later tests revealed that it was actually different. A medical professional explained that this difference was initially concealed to avoid overwhelming the patient with the critical importance of blood type. While these reports suggest that blood type can change, they remain the exception rather than the rule.

Why Blood Test Are Essential Before Donation

Given that a person’s blood type can change, why are blood tests crucial before donations? There are several reasons:

1. Accuracy of Information: Information that a person provides about their blood type may be incorrect. For example, they might make a mistake or simply be unsure. Therefore, relying solely on self-reported information can be risky.

2. Eligibility for Donation: Knowing the correct blood type is crucial for several reasons, including compatibility with the recipient's blood type. A mismatch in blood type can lead to severe adverse reactions, such as hemolytic transfusion reactions, which can be life-threatening.

3. Monitoring Recipient’s Health: In the case of a patient who has undergone a bone marrow transplant, their blood type is regularly monitored to ensure that it remains compatible with their treatments and medications.

The Science Behind Blood Type

Understanding how blood type works requires delving into the molecular level. Each red blood cell contains glycoproteins on its surface, which determine the blood type. These include the A, B, and O antigens, as well as the Rh factor (positive or negative).

For example, an individual with type A blood has A antigens and anti-B antibodies, while someone with type B blood has B antigens and anti-A antibodies. In a similar vein, type AB blood contains both A and B antigens but no antibodies, while type O blood has neither antigen but an excess of both anti-A and anti-B antibodies.

When blood types mismatch, the immune system recognises the donor’s red blood cells as foreign and attacks them. This reaction, known as agglutination, can cause severe complications, including anaphylactic shock and hemolytic disease of the newborn.

Conclusion

In summary, while a person’s blood type can change under specific medical circumstances, such as a bone marrow transplant, the more common and crucial aspect is the importance of accurate and verified blood typing before donation. This process ensures that the donated blood is safe and compatible with the recipient, minimizing the risk of severe complications.