Blood types and donation
April 15, 2023 1:27 PM Subscribe
Why aren't people told their blood types anymore? What happens when people donate blood?
I grew up knowing my blood type and that of my parents, but when my children were born, their blood type was not identified for me. I still don't know it.
My older child was asked to donate blood a few days ago and it got me wondering. How do they even know whether a donor's blood is one they want? Doesn't it make sense to limit donations to Type O? What do they do with blood of less universally useful types -- is it discarded? Do they test each collection as it comes in and label it and sort it? Surely there isn't time to do that when there is an actual emergency and they need to get donated blood into someone? And why don't they just tell people when they're born like they (I guess?) used to?
I grew up knowing my blood type and that of my parents, but when my children were born, their blood type was not identified for me. I still don't know it.
My older child was asked to donate blood a few days ago and it got me wondering. How do they even know whether a donor's blood is one they want? Doesn't it make sense to limit donations to Type O? What do they do with blood of less universally useful types -- is it discarded? Do they test each collection as it comes in and label it and sort it? Surely there isn't time to do that when there is an actual emergency and they need to get donated blood into someone? And why don't they just tell people when they're born like they (I guess?) used to?
When I've donated blood, they have checked the blood type and informed me what it is. They did first ask me if I knew my blood type and then later informed me if I was correct or not. Afterwards, they handed me a card with the blood type printed on it, what region of the country I had donated in (Southern in the USA), and how many units of blood I had donated.
I'm guessing they don't inform a person because it doesn't matter. If you need blood they'll test your type to make sure you get the right one. If you're donating they'll test for your blood type. Just trusting that a person knows their exact blood type is a recipe for disaster.
posted by Brandon Blatcher at 1:43 PM on April 15, 2023 [16 favorites]
I'm guessing they don't inform a person because it doesn't matter. If you need blood they'll test your type to make sure you get the right one. If you're donating they'll test for your blood type. Just trusting that a person knows their exact blood type is a recipe for disaster.
posted by Brandon Blatcher at 1:43 PM on April 15, 2023 [16 favorites]
Not all blood is used during emergencies when blood type isn't known. People with blood conditions like sickle cell and leukemia often need regular blood donations, as do people with scheduled surgeries like open heart surgery. In those cases, it's preferable to give blood as close to the recipient's type as possible.
posted by hydropsyche at 1:51 PM on April 15, 2023 [1 favorite]
posted by hydropsyche at 1:51 PM on April 15, 2023 [1 favorite]
Best answer: Donated blood is tested (in both the US and Canada, certainly) and not just for blood type. It's also processed into three components (platelets, plasma, red blood cells). A member of my family has worked for Canadian Blood Services and if it's a particularly bad batch (incomplete questionnaires, bad labelling, plus testing) you can lose a significant percentage of blood that just has to be disposed of. Testing for type is just one element in the system. When my youngest son needed an exchange transfusion, the wait to call up and prepare the right blood was 4 hours (exchange transfusions are tricky).
(He ended up just barely scraping over the wire for bilirubin counts and not needing it. From living those 4 hours knowing what my family member knows about the blood system, one ends up very very glad that there's testing.)
Extensive tracking of samples and testing has been a feature in Canada since before the Krever inquiry, but certainly afterwards it's been a huge priority. To summarize: Canada was slow to implement HIV/hepatitis B testing, and even after testing improperly heat treated the supply, resulting in hundreds of people, many of them hemophiliacs, contracting HIV in the late 80s.
I can't mention blood donation in Canada without mentioning that gay men were banned from donating in the 80s, and the ban was removed in 2022 with a sexual behaviour set of questions instead (F.F.S.)
Anyways, in summary - unless it's big event (I'm guessing, no direct knowledge here), donated blood is tested, processed, and tracked extensively. When you get the call to donate blood after a tragedy, part of the reason for that call is to restock stores with time for processing - not that there aren't any.
posted by warriorqueen at 1:55 PM on April 15, 2023 [9 favorites]
(He ended up just barely scraping over the wire for bilirubin counts and not needing it. From living those 4 hours knowing what my family member knows about the blood system, one ends up very very glad that there's testing.)
Extensive tracking of samples and testing has been a feature in Canada since before the Krever inquiry, but certainly afterwards it's been a huge priority. To summarize: Canada was slow to implement HIV/hepatitis B testing, and even after testing improperly heat treated the supply, resulting in hundreds of people, many of them hemophiliacs, contracting HIV in the late 80s.
I can't mention blood donation in Canada without mentioning that gay men were banned from donating in the 80s, and the ban was removed in 2022 with a sexual behaviour set of questions instead (F.F.S.)
Anyways, in summary - unless it's big event (I'm guessing, no direct knowledge here), donated blood is tested, processed, and tracked extensively. When you get the call to donate blood after a tragedy, part of the reason for that call is to restock stores with time for processing - not that there aren't any.
posted by warriorqueen at 1:55 PM on April 15, 2023 [9 favorites]
Is it possible that you know because you and your mother had blood type incompatibility? That would explain why you knew your own and your parents, but not your child’s (if he and you/his mother had compatible blood types.
posted by punchtothehead at 1:55 PM on April 15, 2023 [1 favorite]
posted by punchtothehead at 1:55 PM on April 15, 2023 [1 favorite]
Best answer: Every time I've donated through a new group, they've told me what blood type I have, even though I already know.
How do they even know whether a donor's blood is one they want?
There is a constant need for blood. I'm A-, which is relatively uncommon (~6% in the US). In my area, that still means there's over 150,000 people within ~30 miles who are getting into accidents, having surgery, etc. And also, even though I can only take a narrow range of donations, my blood is good for quite a large percentage of the population. There's definitely mass casualty events that will tap the local supply and having people donate because of that need is important, but having a steady supply of all blood types all the time is just part of modern medicine.
Doesn't it make sense to limit donations to Type O?
No, because there's not that much of it.
What do they do with blood of less universally useful types -- is it discarded
Blood stays good for roughly 1.5 months after donation. There is some wastage, but mostly platelets because they have the shorter shelf life. This beats having people die from lack of available blood, but there is room for improvement.
Do they test each collection as it comes in and label it and sort it?
Theoretically, all blood is tested. Getting the wrong type of blood in a transfusion causes an immune response called a transfusion reaction. Suffice it to say that it's bad when that happens. Blood is also screened for HIV and other known blood borne diseases as part of that, which is part of what leads to the above mentioned wastage.
Surely there isn't time to do that when there is an actual emergency and they need to get donated blood into someone?
Again, there's a constant need for blood. You don't want some lab tech going through sample after sample in a crisis to find something that's a match - you test ahead of time when there's not a time crunch.
posted by Candleman at 2:07 PM on April 15, 2023 [4 favorites]
How do they even know whether a donor's blood is one they want?
There is a constant need for blood. I'm A-, which is relatively uncommon (~6% in the US). In my area, that still means there's over 150,000 people within ~30 miles who are getting into accidents, having surgery, etc. And also, even though I can only take a narrow range of donations, my blood is good for quite a large percentage of the population. There's definitely mass casualty events that will tap the local supply and having people donate because of that need is important, but having a steady supply of all blood types all the time is just part of modern medicine.
Doesn't it make sense to limit donations to Type O?
No, because there's not that much of it.
What do they do with blood of less universally useful types -- is it discarded
Blood stays good for roughly 1.5 months after donation. There is some wastage, but mostly platelets because they have the shorter shelf life. This beats having people die from lack of available blood, but there is room for improvement.
Do they test each collection as it comes in and label it and sort it?
Theoretically, all blood is tested. Getting the wrong type of blood in a transfusion causes an immune response called a transfusion reaction. Suffice it to say that it's bad when that happens. Blood is also screened for HIV and other known blood borne diseases as part of that, which is part of what leads to the above mentioned wastage.
Surely there isn't time to do that when there is an actual emergency and they need to get donated blood into someone?
Again, there's a constant need for blood. You don't want some lab tech going through sample after sample in a crisis to find something that's a match - you test ahead of time when there's not a time crunch.
posted by Candleman at 2:07 PM on April 15, 2023 [4 favorites]
Why aren't people told their blood types anymore?
Doctors won't test your blood type unless it's medically necessary. Insurance won't pay for the test otherwise. I asked for my blood type once while I was getting routine blood work done. I was told that they couldn't do that, and I should donate if I wanted to know. (I did.)
posted by donajo at 2:31 PM on April 15, 2023 [1 favorite]
Doctors won't test your blood type unless it's medically necessary. Insurance won't pay for the test otherwise. I asked for my blood type once while I was getting routine blood work done. I was told that they couldn't do that, and I should donate if I wanted to know. (I did.)
posted by donajo at 2:31 PM on April 15, 2023 [1 favorite]
At one point, people knew because they'd do blood typing in biology class in school, but that went out with HIV, I think.
As someone ineligible to donate blood, I know my blood type only because there was a blood-typing booth at the MN State Fair, the one time I went. It was a means to try to convince people to donate blood (not on-site, but in the future). The volunteer went as far as pulling out the big binder of rules in an attempt to convince me to donate blood. But, obviously, my blood is going to give someone vCJD.
posted by hoyland at 2:39 PM on April 15, 2023 [2 favorites]
As someone ineligible to donate blood, I know my blood type only because there was a blood-typing booth at the MN State Fair, the one time I went. It was a means to try to convince people to donate blood (not on-site, but in the future). The volunteer went as far as pulling out the big binder of rules in an attempt to convince me to donate blood. But, obviously, my blood is going to give someone vCJD.
posted by hoyland at 2:39 PM on April 15, 2023 [2 favorites]
I only first learned my blood type when I donated, and even asked a related question about it here 13 (!!) years ago: Is my blood worth anything?
The second time I’ve come to know my blood type was prior to scheduled surgery, where they typed it to know in advance of potentially needing to do a transfusion during surgery. And in this case they didn’t even tell me my type, I just found out because all my blood test results are online.
posted by cgg at 2:48 PM on April 15, 2023
The second time I’ve come to know my blood type was prior to scheduled surgery, where they typed it to know in advance of potentially needing to do a transfusion during surgery. And in this case they didn’t even tell me my type, I just found out because all my blood test results are online.
posted by cgg at 2:48 PM on April 15, 2023
Casually disclosing blood types has caused a fair number of families to come apart when they realized maternity and especially paternity wasn’t what they thought it was.
I read of at least one school system which was de-emphasizing once popular 'what is your blood type?' modules of biology courses just for that reason, and it wouldn’t surprise me to learn that blood donation organizations are being a bit more circumspect than they once were.
posted by jamjam at 3:38 PM on April 15, 2023 [3 favorites]
I read of at least one school system which was de-emphasizing once popular 'what is your blood type?' modules of biology courses just for that reason, and it wouldn’t surprise me to learn that blood donation organizations are being a bit more circumspect than they once were.
posted by jamjam at 3:38 PM on April 15, 2023 [3 favorites]
UK history, and I only learned when I donated. It had never come up before. No idea what anyone else in my family's blood type is.
Hoyland, as long as you do not have vCJD and are not, in fact, a cow, you may be eligible in the USA now.
posted by How much is that froggie in the window at 3:50 PM on April 15, 2023 [2 favorites]
Hoyland, as long as you do not have vCJD and are not, in fact, a cow, you may be eligible in the USA now.
posted by How much is that froggie in the window at 3:50 PM on April 15, 2023 [2 favorites]
Best answer: punchtothehead mentioned blood type incompatibility - the reason we would check a baby's blood type right at birth would be if we're worried about that. This means that we're blood typing baby if the birthing person is Rh-negative or O blood type. Any other Rh-positive blood type, we're not blood-typing baby simply because it's not necessary or relevant to our care, unless baby needs a blood transfusion.
Now, you might be wondering, why not test every person at birth so that if they need a blood transfusion, they can say, hey, FYI, I'm A+? The answer to that is that there is actually more to blood compatibility than those two antigens. If we think or know someone might need blood but it's not an immediate emergency transfusion, we want a type and screen or crossmatch. This involves checking your blood type and also checking for various different antibodies to make sure you get the most compatible blood. A type-and-screen is only valid for 72 hours! (No, your blood type isn't going to magically change, but you could develop new antibodies that change which specific unit of blood is safe for you to get.) So, if you come in to the hospital and tell us your blood type is A+, that's cool but it doesn't save any time or work; we still need a type-and-screen. So that's another reason why knowing your blood type is largely just trivia except for some pregnancy-related issues.
posted by mandanza at 3:52 PM on April 15, 2023 [11 favorites]
Now, you might be wondering, why not test every person at birth so that if they need a blood transfusion, they can say, hey, FYI, I'm A+? The answer to that is that there is actually more to blood compatibility than those two antigens. If we think or know someone might need blood but it's not an immediate emergency transfusion, we want a type and screen or crossmatch. This involves checking your blood type and also checking for various different antibodies to make sure you get the most compatible blood. A type-and-screen is only valid for 72 hours! (No, your blood type isn't going to magically change, but you could develop new antibodies that change which specific unit of blood is safe for you to get.) So, if you come in to the hospital and tell us your blood type is A+, that's cool but it doesn't save any time or work; we still need a type-and-screen. So that's another reason why knowing your blood type is largely just trivia except for some pregnancy-related issues.
posted by mandanza at 3:52 PM on April 15, 2023 [11 favorites]
Best answer: Our 13yo recently had a school science project of some kind where they surveyed students’ blood types, and asked us about his, which I literally had not given one moment’s thought to in 13 years. Turns out that for both our kids it was on the handwritten “Health Record” we were given at birth and took to pediatrician appointments for the first few years. So in New York State/City, at least, it does still seem to be collected, if not particularly salient.
posted by staggernation at 4:14 PM on April 15, 2023
posted by staggernation at 4:14 PM on April 15, 2023
If you donate through the Red Cross, they tell you your blood type, and if you use the app it identifies your blood type right on the front page! The app also shows your “blood journey”: you can see how long it stays in the testing phase, how long it stored and if and when it’s used. There is a chance of course it wouldn’t be used, but it’s a mostly painless and quick procedure that can literally save someone’s life, so I think it’s worth the risk that it might be discarded.
Another important thing to know as a potential donor: if you have a O- blood, have been pregnant and test negative for a certain virus, your blood is especially in need for sick newborn babies.
posted by gryphonlover at 4:40 PM on April 15, 2023
Another important thing to know as a potential donor: if you have a O- blood, have been pregnant and test negative for a certain virus, your blood is especially in need for sick newborn babies.
posted by gryphonlover at 4:40 PM on April 15, 2023
Best answer: Any time you're going to be giving or receiving blood products, you will be typed first for safety. Self-reporting is not good or reliable, so there's very little reason for you to know that information. It is probably buried in a medical chart somewhere, but you are never going to be expected to provide the information.
All donated blood products are tested for blood-borne pathogens before becoming available to be used. There is no emergency in which someone would just carry your blood over to someone else and plug it in, because being in a train wreck or tornado should not result in hepatitis. Blood donors are pre-screened for risk factors for the biggies and will be turned away if they are within a high-risk timeframe for things like HIV or malaria/Dengue fever (which has knocked me out of donation several times, after traveling to some parts of Mexico that were higher-risk at that time), with the HIV rules still being pretty ridiculous in many places and some really inconsistent global restrictions around vCJD.
And yeah, it's more than just type. There are blood-borne pathogens that are so common in the general population that those blood products can be given to most but not some kind of immunocompromised people. I am O- and so very popular, and I am also cytomegalovirus positive, so my products wouldn't be given to babies. But I emphasize you do not need to know this information (and in fact I only know because of some small print on my donor record, I have never been told my status), they will test for it every single time.
posted by Lyn Never at 4:47 PM on April 15, 2023 [3 favorites]
All donated blood products are tested for blood-borne pathogens before becoming available to be used. There is no emergency in which someone would just carry your blood over to someone else and plug it in, because being in a train wreck or tornado should not result in hepatitis. Blood donors are pre-screened for risk factors for the biggies and will be turned away if they are within a high-risk timeframe for things like HIV or malaria/Dengue fever (which has knocked me out of donation several times, after traveling to some parts of Mexico that were higher-risk at that time), with the HIV rules still being pretty ridiculous in many places and some really inconsistent global restrictions around vCJD.
And yeah, it's more than just type. There are blood-borne pathogens that are so common in the general population that those blood products can be given to most but not some kind of immunocompromised people. I am O- and so very popular, and I am also cytomegalovirus positive, so my products wouldn't be given to babies. But I emphasize you do not need to know this information (and in fact I only know because of some small print on my donor record, I have never been told my status), they will test for it every single time.
posted by Lyn Never at 4:47 PM on April 15, 2023 [3 favorites]
I did the A/B test in bio class in the early nineties and mine was inconclusive. Now I know my type from donating but they never told me, it was just written on something I read. I just started donating again with the same organization and they have never asked nor told me what my type is.
posted by soelo at 5:14 PM on April 15, 2023
posted by soelo at 5:14 PM on April 15, 2023
Not really answering the question, as many have already covered it well, but you can buy kits on amazon pretty cheaply and test yourself...
posted by Tandem Affinity at 6:21 PM on April 15, 2023
posted by Tandem Affinity at 6:21 PM on April 15, 2023
My kids are 7 and 9 and the hospital told me their blood type as soon as they were born. I’m O+ so there wasn’t any concern for me but it must have been a routine test for the babies (they also had to draw blood anyway because they were getting glucose tests for being so huge, so that might be why). I have an O- daughter and an O+ son.
This was in MA, dunno if it differs in other parts of the country.
posted by lydhre at 11:36 AM on April 16, 2023
This was in MA, dunno if it differs in other parts of the country.
posted by lydhre at 11:36 AM on April 16, 2023
My mother is an O-, so she's donated gallons of blood so far in her lifetime. I am a B-, and my ex husband was A+, so when we had our kids there were the usual RH concerns. I had a shot after the birth of my first, as he was A+ like his dad. My second was B- like me. I actually am amazed that more people don't know their blood types. But on second thought, I can see how it's not easily available to everyone.
posted by annieb at 12:50 PM on April 17, 2023
posted by annieb at 12:50 PM on April 17, 2023
Lately you do have to be type O to donate only red blood cells to the Red Cross. This is the apheresis machine that separates the red cells from the plasma and returns the latter to you. As noted above, the plasma and platelets for non-O donors are more valuable.
posted by wnissen at 3:45 PM on April 17, 2023
posted by wnissen at 3:45 PM on April 17, 2023
This thread is closed to new comments.
posted by Stacey at 1:39 PM on April 15, 2023 [9 favorites]