Why is blood transfusion dangerous if the groups match?

If the blood groups match, blood transfusions are not dangerous. In fact, they are lifesaving procedures that help replace lost blood or to treat certain medical conditions.

Blood group compatibility is determined by the presence or absence of certain antigens on the surface of red blood cells. When a person receives a blood transfusion from a compatible donor, the recipient's immune system does not recognize the donor's red blood cells as foreign and does not attack them.

However, if a person receives a blood transfusion from an incompatible donor, the recipient's immune system may attack the donor's red blood cells, causing a condition called a transfusion reaction. Transfusion reactions can range in severity from mild to life-threatening, and can include symptoms such as fever, chills, nausea, vomiting, shortness of breath, and low blood pressure.

In some cases, a transfusion reaction can lead to kidney failure, liver damage, or even death. Therefore, it is essential that blood transfusions only be performed with compatible blood.