Blood types are a 20-million-year mystery

Do you know what your blood type is? It’s a pretty basic health question with a pretty bizarre history. We take a look at some ill-fated blood experiments from yesteryear, and try to figure out why it is that all blood isn’t alike. And, our intrepid video director Cory Zapatka takes the question into his own hands with a blood typing kit and a needle...

"Blood Grouping" footage by ICI Productions via CC BY-NC 2.0 UK"

Video: William Poor, Cory Zapatka
Additional Camera: Christian Mazza
Graphics: Alex Parkin
Audio: Andrew Marino
Director of Audience Development: Ruben Salvadori
Social Media Manager: Dilpreet Kainth

[VergeScience]

Do you know your blood type? How’d you find out?

[conniechloe]

To all those who donate blood, I am still alive because of you. I have received about 20 blood transfusions because of blood cancer over the last 4 years and now it looks like i will be in long term remission. I wish I could thank every person whose blood has coursed through my body. (acute myeloid leukemia)

[arthurg]

There are 2 antigens *A* and *B*
Blood group *A* - has *only A* antigens
Blood group *B* - has *only B* antigens
Blood group *AB* - has *both AB* antigens
Blood group *O* - has *neither A nor B* antigens

And there is an *additional protein* called *Rh factor*
If the Rh factor protein is *present* it is denoted by *+*
If the Rh factor protein is *absent* it is denoted by *-*

If a patient receives blood that has an antigen or protein that the patient's blood does not contain then the blood is *harmful* for the patient

If the patient receives blood that does not contain any antigen or protein that is not in the patient's blood (and some of the antigens or proteins that the patient's blood contains can be absent from the blood) then it is *safe* for the patient

[TRKWP]

as an O- from a small city on the great plains I remember being contacted by the police to please report to the hospital to donate to another O- who was in dire straits. one was a baby the other was a minister.

[StrongMed]

Nicely produced video, but a couple of corrections.

First, when your body's immune system attacks transfused red blood cells from a mismatched donor, it's not an "autoimmune" response as stated; autoimmune means attacking one's own cells.

Second, there is no hospital in the developed world that would ever take the word of a patient regarding their blood type at the time of a transfusion - particularly if it was from a do-it-yourself kit they ordered over the internet. If there isn't time to cross-match blood, the patient gets O negative; if there is time, they always get cross-matched. The risk of death from ABO incompatibility is too great to rely on an acutely ill person's memory of an infrequently relevant part of their medical history.

[madhermit]

My father was blood type A- and when he received the universal blood type "O" he would become very ill. When his doctor found out his children were A- he requested we do designated donations for my father as we all were A-. He never became ill when he received "A-" blood. I agree that our blood is very unique, meaning everyone. Hopefully one day scientists will find out more.

[Eveandwolf]

i'm skeptical when they say someone like william harvey "discovered" that blood flowed through the body. many ancient cultures could of already have been aware of this, like the Egyptians

[CurlyChrizz]

0 neg . Found out when donating the first time and they are after my blood like vampires :-D

[brucerogermorgan]

I was a regular donor until I became ill a few years ago, that's when I found out my blood type is A2+. Then I became a Plasma donor for a while. Blood plasma is given to Haemophiliacs to control bleeding. It's a weird procedure but I was happy to be able to help. I'm sad that I can no longer be a donor, but I'm pleased that I was able to for so long.

[david.ricardo]

in Latin America the blood type is in your ID.

[leoeostewart]

There is absolutely no way that a doctor would transfuse blood on the basis of what the patient thought their blood type was. The chances of that patient incorrectly remembering it is just too high. Thus knowing your blood type is just not that practically useful.
Transfusions are a particularly tightly regulated area of medicine. Patients blood will always be checked before a transfusion, and if this isnt possible because of an emergency they will be given O -ve. I've seen patients have their blood cross matched (checked) multiple times due to having different operations on different days. The blood bank won't even trust an old cross match result from a month earlier, it will be rechecked again.
- Final year medical student NZ

[vladdracula]

Type O negative is not just a useful blood type, but a great band as well.

[Yggdrasill]

Holy shit there are actually people who grow up without knowing their blood type WTF, where i'm from we all get tested at birth so we know all our life about it.

[LashanR]

I've been wanting to know my blood type since high school and always wanted to donate blood, but whenever the donation buses come around I always end up having a bit of a cold :/ This year.

[ashleymstewart]

For everyone who is Rh - ( I’m O) and donated blood . I wouldn’t be here without you guys . I have systemic Lupus and when I gave birth to my daughter I almost had Mitral Valve prolapse. I now have permanent cardiomyopathy and leaky mitral valve . I get a echocardiogram every 6 months with my cardiologist. I always wished I could donate my blood because I know only 15% in the world has my blood type . Also I’m so grateful for the RhoGAM shot . I wouldn’t have my two miracle babies

[Ecolopa]

Yay, finally a subject I can elaborate on! Warning, this will be a long read:

Your blood type depends on what antigens are on the outside of your red blood cells. Think of antigens as small markers that cover your red blood cells. As the video mentioned, the main blood types in humans are from the ABO blood group. People that have type AB blood have A- and B-antigens on their red blood cells, while people with type O blood have neither A- nor B-antigens on theirs.

It's important to give patients blood, that is compatible with their ABO blood type, like the chart at 2:53 indicates. That is because the body automatically creates antibodies against the ABO antigens, that their own red blood cells don't have. E.g. people with type O blood automatically have antibodies against A- and B-antigens (anti-A and anti-B antibodies), while people with blood type A only have antibodies against B-antigens (anti-B antibodies). What are antibodies, you might ask? In our case here, they're little compounds, that can latch onto their corresponding antigen, e.g. the anti-B can latch onto B-antigens on someones red blood cells. When an antibody latches onto an antigen, it kind of tells the body, that this is a foreign object, and this can cause the body to attack the red blood cell. Our immune system also uses antibodies to attack e.g. bacteria and other stuff.

The ABO blood group system is very important, precisely because we automatically create these antibodies, against the antigens we don't have. So if you have type A blood, your blood is already filled with anti-B antibodies in your blood, even if your body has never actually "seen" a B-antigen before.

What's this about positive and negative blood then? This is another important antigen, the Rh-D antigen (that's why one of the circles on the blood type card at 4:24 says anti-D, because there are antibodies against the Rh-D antigen on that circle, if you have the Rh-D antigen on your red blood cells). You might've heard people say "I'm Rhesus positive" or something like that. That's referring to the Rh-D antigen. This antigen is very important, because it can also create some complications, when people get blood transfusions. However, people who are "Rhesus negative" don't automatically create antibodies against the Rh-D antigen - we only create it when our bodies are exposed to the Rh-D antigen. That's (also) why the ABO blood group system is kind of special.

We also have other blood group systems, like the Duffy blood group system mentioned in the video. In fact, the Rh-D antigen I mentioned earlier is part of a bigger Rh blood group system. Some of the most important "secondary" blood group systems (with some of their important antigens in parentheses) are the Rh system (D, C, c, E, e), the Kell system (K, k, Kpa, Kpb), the Duffy system (Fya, Fyb), the Kidd system (Jka, Jkb), the Lewis system (Lea, Leb), the MNS system (M, N, S, s) and the Lutheran system (Lua, Lub).

Everyone has some of these antigens on their red blood cells, along with their ABO blood type. E.g you can have A+ blood (i.e. A-antigen and RhD-antigens on your red blood cells), and also have K, E, Jka and C antigens alongside them.

However, these "secondary" blood group systems aren't as important (with the exception of Rh-D) for normal people, since most people only naturally have antibodies against the ABO blood group system. The body doesn't automatically create antibodies against these "secondary" antigens. However (!), if someone *has* antibodies against some of these "secondary" antigens, they'll get blood that corresponds to their ABO/RhD type *AND* that's negative for whatever "irregular" antibodies they've produced against these "secondary" antigens. So if you're hospitalised, and you need a blood transfusion, then the blood bank will test you for your ABO/RhD blood type, and they'll also do an "antibody screen test" against these "irregular" antibodies...unless you need blood *right now* - then you'll get O- blood, as the video mentioned.

Phew...if anyone spots any mistakes, please, feel free to correct me! I'm still just a poor student, haha.

[Cyian]

Me: Whats your blood type, quickly you're losing blood!
Grandfather: B Positive
Me: I'M TRYING MY BEST HERE

[X-Gen-]

High 5 to all my A+ blood family out there. 🙏

[erikanderson]

I have my masters in Medical Laboratory Science. In the developed world, knowing your blood type is trivial. UNDER NO CIRCUMSTANCES would you ever receive blood based off of what you say your blood type is. Compatibility of the blood is tested before in the lab.

[kindeep]

Wait I thought it's normal for one to know their blood type... I just know it and I don't even know who told me my blood type.