- Do you know your blood type? If you haven't been in
any medical situations where blood type is
important, you might not. I certainly don't, and I
can't speak for everyone, but most of my friends and family said that they too had no idea. My dad earned half a point
for correctly answering red, among other responses from
my friends, like boiling. And frozen. But there's actually a lot
of mystery around blood. We know that there are
eight main blood groups that make up most of
the world's population. A, B, AB, and O. And a negative and positive for each. But it turns out that
scientists still don't know why we evolved different blood types. And that may remain a
mystery for a long time. But for now, science can at
least tell me a little bit about my own blood. (mysterious music) That curiosity led me to buy this test. It's called the EldonCard. It's cheap, simple, and it
takes just a few minutes to determine your blood type. All you have to do is prick your finger, apply four drops of
blood, and mix the samples with the different serums. Depending on how the samples
agglutinate, or clump, you can determine your blood type. In developed parts of the world, it's not crucial to know your blood type off the top of your head. Doctors will typically
run tests before any major procedure, and if there's
any doubt in a medical emergency, you'll most likely
receive O negative blood. That's the universal donor
blood that's safe to give to any A, B, AB or O recipient. But what would happen if you received the wrong type of blood? Well, some curious minds
found that out the hard way. For thousands of years, nobody
really understood blood. A Greek doctor from 200 CE
believed that it was created from food and liver. And this school of thought
lived on for nearly 1500 years. It wasn't until the early 17th century that a British doctor named William Harvey discovered that blood actually
circulated through the body. And this spawned a new age of
experimentation with blood. In 1665, an English
physician successfully kept one dog alive by transfusing
it with the blood of another dog. But then things got kind of weird. Just two years later,
doctors began experimenting with xenotransfusions. That is, transfusing
humans with animals' blood, such as sheep. And those human patients died. It wasn't until 1900 that
we finally realized people and animals actually have
different types of blood that determine whose
blood can mix with whose. And that's where those different
letters come into play. If you're type A, your
immune system will perceive type B blood as an intruder,
and trigger an auto-immune response that can cause kidney failure, extensive blood clotting, and even shock. And the reverse is true of type B blood. The immune system will attack type A. AB blood, however, can
accept both A and B blood without triggering that
auto-immune response. Things start to get a
little more complicated when you introduce the rhesus factor, or the negative and positive
part of your blood type. Positives can accept
negatives, but the opposite is extremely dangerous. And to further complicate
things, scientists have discovered dozens of more blood types, such as the Duffy blood
group, which can determine your susceptibility to malaria. Or the Hh blood type, which 1 in 10,000 people in India have. But the vast majority of humans fall into this A, B, O system. (mysterious music) As for why humans evolved
this complicated system of blood types and compatibility,
we don't really know. The original mutations
are thought to date back nearly 20 million years. But look, whatever the biology
is behind blood typing, it's a real, practical thing that matters. And in many parts of the
world, knowing your blood type is fairly common knowledge. In Japan, it's linked to your personality. Sort of like a horoscope. You can even add your blood
type to your Facebook profile. And in 2011, former Japanese
minister of reconstruction Ryu Matsumoto blamed his
irritable and impetuous behavior on his blood type, type B, after he was forced to
step down from his seat. Personality types aside,
I did this EldonCard test because it's just not a bad
idea to know your blood type. If you're traveling
somewhere that's rural, or doesn't have access
to advanced medicine, it's good for you and your
traveling companions to know your types, just in case of
an accident along the way. And in a big emergency closer
to home, blood banks often put out calls for donors
of a specific type. And remember, if you're type O negative, you're an extremely
useful universal donor. So, knowing your type can give
you a little peace of mind. And hey, if you're in Japan it's a great way to break the ice. Although, type Bs don't really
have the best reputation. But I'm fine, I'm A positive. Hey everyone, just a note
that you can also find your blood type by donating
blood, serving in the military, or just by asking your doctor
during routine blood work. But the EldonCard is fun,
and kind of do it yourself. If you haven't already,
please like, comment, and subscribe to our new
Verge Science YouTube channel, where we're putting
out a video every week. Thank you.
No one has any practical need to know their own blood type as no blood banker will take anyone else's word over their own work.
Source; former blood banker here.