Name: There Are Millions of Blood Types
Uploaded: 2020-03-30T03:11:07.000Z
Duration: 5 min 44 s
Description: Thousands of YouTube videos with English-Chinese subtitles! Now you can learn to understand native speakers, expand your vocabulary, and improve your pronunciation...

At some point—like, if you've donated blood—

you might have been asked about your blood type.

And even if you don't know what yours is,

you're probably aware that you could have

and that your blood can be positive or negative.

because there are potentially millions of blood types out there.

because of the way blood types are defined.

Antigens are anything that can elicit a response

though your immune system normally ignores

And you can find antigens on cells throughout your body,

with different cells having different combinations of antigens.

The ones that matter for blood classification are found

on the surfaces of your body's red blood cells.

your particular blood type depends on which antigens are or aren't there.

that means you have both the A and B antigens in the ABO blood group.

You could be just A, or just B, or if you're O, you don't have either.

But those ABO antigens are just two of over 600 blood antigens

identified by the International Society of Blood Transfusion,

Many of these antigens fit into blood group systems,

like ABO, each of which is defined by a gene at a single site

or by multiple genes that are closely related.

your type for a particular group depends on how your genes translate

into the antigens that end up on the outside of your blood cells.

There are 36 blood group systems currently recognized.

and the variants you have or don't have for all of those 600-plus antigens.

Which is why we can say that there are millions of potential blood types.

and that's because many of these antigens are found in practically everyone,

while others are present in only a few individuals.

the SARA antigen has only ever been seen in two families,

while 99.96% of people have the Vel antigen.

And blood groups can get really complicated, too.

That's the group that gives you a positive or negative blood type—

the positive part generally means you have the Rh antigen called Rh(D).

whether your blood is considered positive

or negative may depend on how much of the antigen you have in your system,

since that can impact what sorts of antibodies your immune system makes to protect you.

And D is just one of over /60/ known antigens in the Rh group.

So positive or negative doesn't even begin to capture your overall Rh blood type.

In fact, one of the rarest blood types in the world occurs

if you have none of the antigens in the Rh group.

If you're one of the about 50 people with this blood type—

your body will reject the blood from practically anyone else.

And the Rh group isn't the only blood group where having no antigens

Its antigens are proteins that help the lungs and kidneys perform essential functions.

that determine a person's Diego blood type.

But unlike the ABO group, where “O” or the lack of antigens is most common,

there has only been one documented case of someone lacking both of these key Diego antigens.

Sometimes, though, having no antigens can help you out.

one of the malarial parasites uses antigens in the Duffy blood group

so having no antigens from that group can make you more resistant to the disease.

But it also means there's a chance that your body will attack another person's blood

since the cells you receive could have Duffy antigens on them that your body sees as foreign.

The good news is that despite all the potential blood types you could have,

for the most part, the ABO-Rh blood typing we're used to

does a pretty good job of matching people's blood.

if you receive blood from someone with the same ABO-Rh type,

there's a 99.8 percent chance your blood will be compatible with your donor's.

your body's immune system doesn't go after every antigen equally,

so you don't usually need to know what version of every single known antigen you have.

there are ways that doctors can tell if you have a rare blood type.

they can screen for unexpected antibodies that could potentially target donated red

where your blood is mixed with a donor's to see how the two react.

Doing these two steps racks your safety margin up to 99.95 percent.

And if you do happen to have a rare blood type like Rh null,

Efforts like the International Rare Donor Panel work hard

to make sure you can get the blood you need, no matter where in the world you are.