There Are Millions of Blood Types


[ intro ] 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 A, B, AB or O blood, and that your blood can be positive or negative. But that’s not the whole story, because there are potentially millions of
blood types out there. There are so many possible blood types because of the way blood types are defined. You see, your blood type is defined by the antigens present in your blood. Antigens are anything that can elicit a response from your body’s self-defense system, though your immune system normally ignores the ones that belong to you. 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. Simply put, your particular blood type depends on which
antigens are or aren’t there. Like, if you have AB blood, 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, and the list hasn’t stopped growing yet. 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. And all of us have these genes— 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. So your full blood type, if written out, would include all 36 of these groups 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. Of course, there are only 8 common ones, and that’s because many of these antigens
are found in practically everyone, while others are present in only a few individuals. For example, 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. Just look at the Rh blood group. That’s the group that gives you a positive
or negative blood type— like, if you’re AB+, the positive part generally means you have
the Rh antigen called Rh(D). But, to make things more confusing, 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— which is known as Rh null— your body will reject the blood from practically
anyone else. And the Rh group isn’t the only blood group
where having no antigens can be a matter of life or death. Another example is the Diego group. Its antigens are proteins that help the lungs
and kidneys perform essential functions. Like with the ABO group, there are two primary antigens, a and b, 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. For example, one of the malarial parasites uses antigens
in the Duffy blood group to target and infiltrate cells, 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 if you’re given a transfusion, 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. With this system, 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. For some reason, 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. And if you do want to be extra sure, there are ways that doctors can tell if you
have a rare blood type. For example, they can screen for unexpected antibodies
that could potentially target donated red blood cells, or perform crossmatching, 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, don’t fret. 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. One person needing a transfusion had a rare
blood type delivered from the UK to Cameroon. That’s about four thousand miles away! So even if your blood is literally one in
a million, you can be pretty confident that you’ll
be able to find someone whose blood matches yours. And, I guess, you could say that’s one of
the parts of being human — having something in common with other people while being unique in your own special way. Blood types ultimately boil down to microscopic
differences between red blood cells. And if you were to zoom in to see those differences
and really watch what goes on in your own bloodstream, you’d see a bustling and bizarre world. In fact, when you look at pretty much anything
under a powerful enough microscope, all sorts of wonderfully fantastic lifeforms
are revealed. And that’s kind of the point of our new
sister channel produced by Complexly: Journey to the Microcosmos. Journey to the Microcosmos is all about bringing
you closer to the world of very, very small things in a relaxing way. It pairs James Weiss’s incredible microscopic
footage with Hank Green’s soothing narration and Andrew Huang’s meditative music, so you can just kick back and marvel at the
microscopic realm. You can check it out for yourself at the link
in the description. And as always, thanks for watching! [ outro ]

100 thoughts on “There Are Millions of Blood Types”

  1. Well… I've learned so much from this video that I have to watch it a few more times.
    Great information that seem updated since I first heard of blood types. I say
    thank you for caring enough to give us some decent education.

  2. Don't take the blood test. It is so rigged.
    I studied endless nights and ended up with a B-

    Then some bloke who has never touched a textbook in his life gets A+

  3. Important to understand "screening and cross-matching" is NOT done by doctors.
    It is done by Medical Lab Scientists in the lab.
    With a little knowledge, practically anyone can do the ABORh blood drop screening cards
    but the more complicated stuff is done in the lab by lab people who understand it.
    Credit where credit is due!

  4. Did you know dogs have at least 7 antigen groups? And that from the point of view of transfusions they rarely matter at all? Cats are typically A, B, or AB; A cats can accept B blood once, but B cats seem to be born with antibodies to type A blood. Fun stuff.

  5. There's actually all of the negative RH blood types in my family 😀 My dad is O-, my mum is AB- and me and my eldest brother is A-, whereas my older brother is B-.
    So if someone we know needs a blood transfusion, our family has the blood types for it XD (Since Negatives can donate blood to both positive bloodtypes and negative blood types XD)
    (Then again, they actually only need my dad, since O- can donate to all RH positive and negative blood types)

  6. I have a weird-ish blood type! I found out when I wanted to donate a kidney. A+, non-A1. (Meaning that they didn't test to find what specific variant of A it is, but they know it's not the most common one.) It only has about 20% of the the A markers that A1 has. That means that, for donating/receiving blood, it's A, but for organ donation some of my organs can go to O recipients.

    me: "Sooo it's like A-light?"
    Doc: "… Yes. Yes! That's exactly right. I'm going to use that explanation next time."

  7. The International Society of Blood Transfusions, best known for their constant beefing with the Jehovah's Witnesses…

  8. Hey SciShow, doctors don't do antibody screens or crossmatches! Medical laboratory technicians, scientists, and technologists do. We're a pretty quiet part of the healthcare team, but we are the ones doing a majority of the science that goes into ensuring your health.

  9. With regards to what's said at the end of the video about "being confident that you''ll get someone's blood that matches yours". Atleast in India right now there is a shortage of blood, even common blood types; not that easy trust me.

  10. I'm the impossible blood type. Both my parents are A, my mom A-, my dad A+ (yes, that did cause pregnancy issues), and I'm AB+. And my cousin has the same impossibility: his parents are 0 and A, but he's also AB, but AB-…
    And both these situations are technically impossible

  11. that's cute if your doctor doesn't tell you you're not allowed to know your blood type. Apparently it's a secret for everyone in my homecountry.

  12. Some surprise?
    2 500years ago was written in bible abstain from blood. And in this days, thanks to JW, we know how much it's true.
    And it's surprise how low blood we need for surviving if we can hold pressure with supplement.

  13. See, im an O+, but because of a genetic condition if the person who donated ate anything containing certain amino acid compounds within 24 hours…i could have a nasty reaction.

    Learned that the hard way…

  14. Great video! Just one thing: it’s not doctors doing the compatibility testing. That would be medical technologists like me!

  15. 2:32 I’m pretty sure that number is outdated since I’ve personally seen several Rhnull reports. So yea, there must be much more than 50 people already.

  16. 4:05 its not just me right?
    The word "crossmatching" IS colored differently

    Im trying to get feedback if Im colorblind, sense heightened, or sleep deprived

  17. My exhusband is A- and I'm B+. We had 2 children a female A- and a son B-. When he was going to have an operation neither of us could be used for an emergency. That has concerned me for years especially since B- is not a common blood type.

  18. I don't know what blood type I am but I think I may be a rare blood type because of strange chromosome different. I want to donate blood but I can't because I get dehydrated very easily and is scared of the sight of blood and has passed out with needles in the past.

  19. Fundies: ReStRiCtIoN oN mIxInG fOoD iN cLaY pOtS wHiLe cOoKiNg mEaNs yOu cAn'T hAvE tRanSfuSiOnS eVErrr! – it's sad to see nutjobs deluded to such degree…

  20. either my grandma had "Rh null" blood or something else similar, because i remember hearing about how she had to donate blood when she was healthy (she had a lot of weird health problems) in case they needed it later because her blood type was super weird. and that her sister could have donated for her except she had been exposed to something or other as a kid that means you can't donate blood (like TB or something idk)

    and now my mom is confused by my question "i think she was rh negative" "yeah no a shitton of people are rh negative this is a different thing i'm asking"

  21. Okay, please don't fight about what I'm about to say in the replies, but…. GOD IS SO AWESOME AND THIS ABSOLUTELY PROVES IT!! There, nuff said…. 😄💖

  22. A couple of factual and personal problems with this video. First of all, Doctors don't test your blood type!! There is a branch of medical testing (performed by MLS and MLT's) devoted to transfusion science. There are only around 6 blood grouping systems that are clinically significant, and these are generally related to how much you express and the affinity of antibodies produced to them, for example the duffy system has a few antigens that are important and a few that aren't. Although it may not be completely understood its not something we dont understand at all. An interesting note about O type is that it is not the absence of an antgen as implied in the video but the absence of part of the antigen. ABO antigen has 2 important parts, the part that holds onto the cell is called the H part and attached to this is either the A or B molecule. If you are type O you dont have the A or B molecule, just the H part. There is a subgroup of O group people who havent got the H part at all, so they have no antigen at all (they are called Oh or O-bombay) it is most common in South Asia specifically in India and Sri Lanka. Anyway thats my rant, i don't know if anyone would read this but if you did i hope you learnt

  23. My friend got hit by a bus while crossing the road together on our bikes. I immediately ran up to him and called an ambulance. He was bledding heavily. I'll always remember his last words. He kept telling be to "be positive."

    Miss you man. 🙁

  24. Every time I go to donate blood, my iron levels are lower than the last time, which I don't get. I don't make a habit of bleeding everywhere, so you'd think my body would be able to recover in the interim months. They keep calling me back though. I don't even like giving blood, I just like the free snacks afterwards.

  25. That’s great and all but kidney organ transplant needing patients with “O” blood end up waiting twice as long as the average transplant patient which increases mortality rates.

  26. I wanna stick my blood in someone and see what happens… The last time I got sick was over 11 years ago. Thanks to my mutant blood type X (I don't know what type I have).

  27. This video is the reason why we need a consistent and DIVERSE blood donor pool. Race plays a large role in the genetic makeup of your extended blood type, and if you need a rare blood transfusion, you have a higher probability of being compatible with a donor the same race as you.

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