View Full Version : Blood Type

04-14-2009, 10:38 PM
How did the blood types get the designation of A, B, O, & AB? Why "O" and not "C"? Do the letters correspond to anything relating to how the blood types are different?

04-14-2009, 11:03 PM
A and B correspond to the two antigens that can be present on the surface of blood cells, and the names are descriptive of what's present. Type A has the A type, type B has the B type, type AB has both, and type O has none. (Think O as in zero.) Presumably, using C instead would imply that there was a third antigen in play.

Wiki page with some good diagrams. (http://en.wikipedia.org/wiki/ABO_blood_group_system)

04-14-2009, 11:05 PM
Deleted. Beat.

04-14-2009, 11:07 PM
Somewhat of a WAG, but it was probably the notation used by the original researchers who named them in the first place.

A and B are natural choices, being the first two letters of the alphabet and are used to describe one of two antigens found on red blood cells. O isn't C because it doesn't actually describe anything - it is the absence of either the A or B antigen which defines someone with O blood. I assume the original notation was some form of null symbol, and it became O for convenience. AB is simply a case of someone with both the A and B antigens in their blood.

ETA: Beat, but not deleted ;)

Lynn Bodoni
04-14-2009, 11:11 PM
A has one type of marker. B has another type of marker. AB has both markers. O has neither.

Or at least, that's what I remember from high school biology.

We also have the positive and negative Rh (found in rhesus monkeys, not to be confused with peanut butter cups) and m and n markers. Currently, humans are known to have 30 markers/antigens.

Googling "blood types" will turn up all sorts of info, such as the bit about humans having 30 different antigens.

Lynn Bodoni
04-14-2009, 11:20 PM
A little more Googling shows that it's not blood type O, as in the letter between N and P. It's 0, or null, as in "concept of zero". So if someone has no blood antigens of the type A or B, then he has zero, or 0, blood antigens in the AB system.

04-15-2009, 12:00 AM
While the "o" symbolizes "zero", the convention is to use the letter. Tell someone you're a type Zero Negative will lead to a lot of double-takes.

04-15-2009, 07:13 AM
While the "o" symbolizes "zero", the convention is to use the letter. Tell someone you're a type Zero Negative will lead to a lot of double-takes.

It's called Cero Negativo in Spanish, though. It's one of those little things...

04-15-2009, 03:43 PM
Thanks! I was a little confused. I could understand the bit about A and B being the first two and that O blood type did not have the A or B antigens but I was confused by the use of the letter "O". I see now it is really a 0 (zero) (I read the Wiki page but just wasn't glomming that little fact.) :smack:

Tom Tildrum
04-15-2009, 04:57 PM
In countries that do not use a Western alphabet, how are the blood types designated?

04-15-2009, 10:09 PM
In both Japan and South Korea, blood types are designated in the usual manner they are in the US. There's a bit of an odd phenomenon in both Japan and Korea, though. Instead of asking a potential date, "What's your sign?" people ask, "What's your type?" meaning blood type. The kicker is that the general public never answers with the Rh Factor, just "I'm type O" or "I'm type AB."

Exapno Mapcase
04-15-2009, 11:31 PM
Odd for us, not for them.

Blood types in Japanese culture (http://en.wikipedia.org/wiki/Japanese_blood_type_theory_of_personality)
There is a popular belief in Japan that a person's ABO blood type or ketsueki-gata (血液型 ?) is predictive of their personality, temperament, and compatibility with others, similar to the Western world's astrology. This belief has carried over to some extent in other parts of East Asia such as South Korea.

Ultimately deriving from ideas of historical scientific racism, the popular belief originates with publications by Masahiko Nomi in the 1970s. The scientific community dismisses such beliefs as superstition or pseudoscience.