How can blood be Rh negative (with no antigens) and (for example) be AB (with AB antigens)?

It’s sort of two different things.

Blood type and Rh factor both do have to do with antigens/proteins in the blood.

Blood type is inherited from your parents and you have either A, O, AB, or B. Everyone fits into one of these four.

Rh factor is another defining characteristic of the blood, also having to do with inheritance, and you can be either Rh positive or Rh negative. If you are negative you don’t have the Rh protein.

So, you can be A positive or A negative, B positive or B negative, AB positive or AB negative, or O positive or O negative.

O negative is the universal donor not having any proteins that can harm someone with other blood types. If you introduce a protein that the recipient doesn’t have, that’s when you get a problem, and why blood type is so important.

Do you need it defined more than that?

Do you have practice questions you can take? To make sure you understand what you need to know?

@JLeslie Yeah, I know that Rh is separate from ABO, I just don’t get how being A/B/AB means you DO have antigens, but at the same time you can be A-, having apparently no antigens as well? Or I might have the definitions wrong?

I don’t remember exactly all the terminology. We need one of the science jellies.

Rh is another antigen. So you can have the antigen for A, but not have the Rh antigen. It’s separate antigens, it’s not like you either are positive antigen or not. It’s that there are a multiplicity of antigens, and which ones do you have or don’t you have.

It’s sort of like having the antigen for A, but not B, so then you are blood type A. Rh is another set, or type, of antigens separate from ABO.

@JLeslie Oh okay I think I get it now, thank you so much!! <3

Read up on it for the test. My answer isn’t very scientific, it’s just the basics for the concept.

Let us know how you do on test.