Question

Anatomy Mini-Tutorial: Blood-Typing

Answer 1

\({\bf{Overview:}}\) there are 4 main blood types (A, B, AB, and O). In addition to having one of these four types, a person can be Rh-positive or Rh-negative (so an example blood type could be B negative)

Why do these blood types exist? Your red blood cells can have antigens on their surface, which are markers that lead to an immune response within the body. Within the plasma (the watery, liquid part of the blood) are antibodies that respond to antigens.



\({\bf{Donating~and~Receiving~Blood:}}\)

A type-A individual has the A antigen and their plasma has anti-B antibodies. That means they can accept blood that has either an A antigen (or no antigen) but the anti-B antibodies will respond to any B antigen, so a person with blood type A cannot accept AB or B blood. type A blood can be donated to types A and AB.

similar logic with type-B. They have the B-antigen and anti-A antibodies so they can accept types B and O but will reject AB and O. type B blood can be donated to types B and AB.

type AB means the individual has both A and B antigens, and thus, no anti-B or anti-A antibodies. Since they don't have antibodies that would reject blood cells, AB individuals are known as universal recipients. However, they can only donate to other AB types

type O means the individual has neither antigen, and has anti-B AND anti-A antibodies. So their blood doesn't have any antigens that would induce an immune response in another person, making type O known as the universal donor. Type O's have both antibodies and will reject any blood with A or B antigens and therefore can only receive from other type O's.

Answer 2

\({\bf{Rh~Factors:}}\) The above rules get a bit more complicated when it comes to Rh-factors. An Rh-negative person can donate to either Rh-negative or Rh-positive individuals but an Rh-positive person can only safely donate to other Rh-positives.

Regarding receiving blood, this means Rh-positives can receive blood from either positive or negative but Rh-negatives can only safely receive blood from other Rh-negatives.

\({\bf{Rh~Factors~and~Pregnancy:}}\)
If the mother is Rh- and the fetus is Rh+ there is the possibility that the fetus's blood will enter the mother's bloodstream. The mother can build up an immunity to the Rh+ antigen. This doesn't always affect the first pregnancy but can be a problem with future pregnancies because the mother's anti Rh antigens will attack the baby's Rh+ blood. Thankfully, there are anti-anti-Rh antibody treatments like Rhogan which will suppress this immune response.



\({\bf{Possible~Consequences~of~Incompatible~Transfusion:}}\) If a person receives a blood type for which they are incompatible, there will be a cross-reaction between the antibody and the antigen that will cause agglutination (clumping of blood) and hemloysis (blood cell rupture). This can cause clotting/organ failure if not treated promptly.

Answer 3

as a side note,

Please donate blood as long as you don't have any physical/mental issues that would prevent you from doing so; your local RedCross chapter can be a good resource for finding places to donate. Note that donating blood is not the same as donating plasma (plasma does not contain RBCs) and you will not receive money for donating blood, but it really does make a difference especially in times of crisis.

Answer 4

Adapted from Human Anatomy, Martini, et. al. 9th edition