Two things say I have different blood types?

Question

According to my birth certificate, I have O+ blood. Recently, I gave blood to the red cross, and my donor card says that I have A-.

What could have happened, and how can I find out for sure? (without having to pay for a blood typing, if possible)

Answer 1

Unless you have had a bone marrow/stem cell transplant, one of these is wrong. I would not worry about until time to donate blood again; bring this up to the technician and you could take a "best 2 out of 3"!

Answer 2

It could be that you have what is known as the Bombay blood group, although its fairly rare. The fact that your rhesus group seems to have changed too makes me think its probably a mistake though.

Answer 3

As moody said, the red cross should figure it out for you if you're willing to donate./

/On a side note, type O blood is the universal donor, but the universal acceptor is type AB.

type O- blood doesn't have eiter A or B antigen, but it has both A and B antibodies, so it can be donated to type A, B, AB, or O, but can only accept type O.

type AB+ blood has both A and B antigen, so it has neither antibody and can accept any type of blood.

also, the + and - refer to the Rh antigen, and Rh - blood types can only accept Rh - blood types.

Answer 4

Possible causes:

1.  You were switched at birth (I'm really not kidding, this does happen occasionally).      -Or-

2.  The lab switched your blood with someone elses when testing it (this is the most likely scenario).

Either way, get your blood tested agian (the red cross will do it for free when you donate).  Until you retest, keep in mind that you can receive blood from an O- donor in an emergency situation.  O- is the universal donor.  (Removed)

------------------- Correction--------------------

Dan is absolutely correct.  AB is the universal recipient.  O+ can only receive blood from O- or O+.  I am very sorry for the misinformation.  Thought for sure I had my facts sorted correctly.  O- is the universal donor however.  O+ is not a universal donor as blood types with a negative may not accept the O+, but all blood types with a positive will accept either of the O blood types.