What’s My Type?


Q: Do I need to know what my blood type is?

It’s funny how things run in waves around here.  I’d never been asked this question in my previous 3 years here, and then 2 people asked it on the same day.  So here goes…

Our blood type is determined by the combination of 3 different antigens that can be present on the outside of our blood cells: A, B and Rh factor.  An antigen is any substance or molecule that triggers your immune system to create an antibody against it (antibody generator).  Depending on the combination you have, your blood type will be A+, A-, B+, B-, AB+, AB-, O+ or O-.  The American Red Cross has a great website that explains what all of the combinations mean in terms of blood compatibility.

To answer the question… no, there is no real medical reason to know what your blood type is.  If you’re ever in an accident where you would need a blood transfusion, for instance, they will test your blood type right there in the emergency room.  Even if you had a copy of your test result in your pocket, they are going to re-check it because it can be done very quickly and it is just too risky to take a chance that it isn’t correct.

Same thing goes for other situations where knowing your blood type might come in handy, like seeing if you are a compatible blood or organ donor.  And blood type isn’t enough to prove or disprove paternity, so if there’s a question of baby-daddy hood going on, you’re going to need more info anyway. 

Since there’s no real medical indication to check your blood type, your insurance company probably won’t pay for it.  However, we do offer an Order-It-Yourself lab service where you can pay to have it checked without having to see a health care provider.  It’s not too expensive – swing by our lab to learn more if you’re interested.

There is another way to find out your blood type… for free!  Donate blood.  Whenever you donate blood with the Red Cross, they check your blood type.  Not only is it free, but you’ll be doing a great service to humanity AND you get free juice and cookies – that’s a pretty sweet deal.

John A. Vaughn, MD
Student Health Services
The Ohio State University