# Do you know your blood type? **URL:** \ **Category:** In My Humble Opinion\ **Created:** [July 25, 2018, 3:06am UTC](https://boards.straightdope.com/t/do-you-know-your-blood-type/818539 "2018-07-25T03:06:22Z")\ **Posts on this page:** 20\ **Page:** 4
**Author:** ![Ulf\_the\_Unwashed](https://avatars.discourse-cdn.com/v4/letter/u/b4bc9f/32.png) [@Ulf\_the\_Unwashed](https://boards.straightdope.com/u/Ulf_the_Unwashed)\ **Post date:** [July 28, 2018, 7:06pm UTC](https://boards.straightdope.com/t/do-you-know-your-blood-type/818539/62 "2018-07-28T19:06:38Z")
Interesting about not testing for blood type in routine labs. My dad was in the hospital for an extended period of time many years ago. They kept sticking him with needles and drawing blood for this and that and the other thing. One day he was curious, so when they came into the room with their blood-taking equipment he asked what this one was for. “Oh,” they said, “we just need to know your blood type.” ---
**Author:** ![Sigmagirl](https://avatars.discourse-cdn.com/v4/letter/s/c89c15/32.png) [@Sigmagirl](https://boards.straightdope.com/u/Sigmagirl)\ **Post date:** [July 29, 2018, 4:09am UTC](https://boards.straightdope.com/t/do-you-know-your-blood-type/818539/63 "2018-07-29T04:09:55Z")
> [@BlueOhio](#): > > I’m O-, CMV neg. The blood bank loves me. I gave regularly until a cancer diagnosis last year but I look forward to being able to donate again in the future. Same, except for the cancer. I wish you well. 14 gallons here. ---
**Author:** ![Snooooopy](https://avatars.discourse-cdn.com/v4/letter/s/ee7513/32.png) [@Snooooopy](https://boards.straightdope.com/u/Snooooopy)\ **Post date:** [July 29, 2018, 6:46am UTC](https://boards.straightdope.com/t/do-you-know-your-blood-type/818539/64 "2018-07-29T06:46:39Z")
I do, and the only reason that it stuck in my head is because I was quite the little academic back in the day, and I just couldn’t believe my blood didn’t get the highest grade as well. ---
**Author:** ![Baron\_Greenback](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/baron_greenback/32/48_2.png) [@Baron\_Greenback](https://boards.straightdope.com/u/Baron_Greenback)\ **Post date:** [July 29, 2018, 5:57pm UTC](https://boards.straightdope.com/t/do-you-know-your-blood-type/818539/65 "2018-07-29T17:57:16Z")
O- here, and was a regular donor until I was given a blood product during an operation. I’m not allowed to donate any more. Boo to BSE! ---
**Author:** ![Jeff\_Lichtman](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jeff_lichtman/32/1531_2.png) [@Jeff\_Lichtman](https://boards.straightdope.com/u/Jeff_Lichtman)\ **Post date:** [July 29, 2018, 7:58pm UTC](https://boards.straightdope.com/t/do-you-know-your-blood-type/818539/66 "2018-07-29T19:58:42Z")
A Positive Would a doctor take a patient’s word for it when ordering a transfusion? The consequences of getting it wrong are serious. I’d think the doctor would want to test it rather than rely on a patient’s memory. ---
**Author:** ![dwyr](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dwyr/32/363_2.png) [@dwyr](https://boards.straightdope.com/u/dwyr)\ **Post date:** [July 29, 2018, 9:13pm UTC](https://boards.straightdope.com/t/do-you-know-your-blood-type/818539/67 "2018-07-29T21:13:26Z")
> [@Jeff\_Lichtman](#): > > A Positive > > Would a doctor take a patient’s word for it when ordering a transfusion? The consequences of getting it wrong are serious. I’d think the doctor would want to test it rather than rely on a patient’s memory. No. The blood bank won’t either. Every patient specimen is tested for type. In addition, every unit of blood that comes into a blood bank from a donation center is retested for type even though the blood center already did it. The blood bank is required to do this - they don’t take anybody’s word because a mistake can be rapidly lethal. ---
**Author:** ![kopek](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kopek/32/337_2.png) [@kopek](https://boards.straightdope.com/u/kopek)\ **Post date:** [July 29, 2018, 9:54pm UTC](https://boards.straightdope.com/t/do-you-know-your-blood-type/818539/68 "2018-07-29T21:54:34Z")
I’ve been a mostly-on-but-sometimes-off blood donor so I know mine. I even have the little record card from the blood bank in my wallet all the time giving that and other info on it. ---
**Author:** ![CelticKnot](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/celticknot/32/3392_2.png) [@CelticKnot](https://boards.straightdope.com/u/CelticKnot)\ **Post date:** [July 30, 2018, 5:29am UTC](https://boards.straightdope.com/t/do-you-know-your-blood-type/818539/69 "2018-07-30T05:29:59Z")
A+ I donated all the time. The first time I gave blood, there was a commuter train crash and there was a call for donors. My dad and sister and I went downtown to donate. I think someone working at the facility had a sense of humor, or maybe it was a coincidence, but the TVs were all tuned to a TV broadcast of _First Blood_. I can’t donate anymore. Years before I started, we lived in Europe. Decades later came mad cow, and if you might have been exposed by living somewhere affected, you don’t get to donate. What’s the incubation period for JK disease? ---
**Author:** ![elfkin477](https://avatars.discourse-cdn.com/v4/letter/e/a9a28c/32.png) [@elfkin477](https://boards.straightdope.com/u/elfkin477)\ **Post date:** [July 31, 2018, 2:07am UTC](https://boards.straightdope.com/t/do-you-know-your-blood-type/818539/70 "2018-07-31T02:07:00Z")
Well, I know it’s O like Mom’s but I don’t know if that’s positive or negative. I thought negative but Dad insists that he and lil bro are A+ and I never heard anything about Mom needing a shot when either of us were born. ---
**Author:** ![Baker](https://avatars.discourse-cdn.com/v4/letter/b/bb73d2/32.png) [@Baker](https://boards.straightdope.com/u/Baker)\ **Post date:** [July 31, 2018, 10:23pm UTC](https://boards.straightdope.com/t/do-you-know-your-blood-type/818539/71 "2018-07-31T22:23:42Z")
Good ol’ A+ here. ---
**Author:** ![Siam\_Sam](https://avatars.discourse-cdn.com/v4/letter/s/d78d45/32.png) [@Siam\_Sam](https://boards.straightdope.com/u/Siam_Sam)\ **Post date:** [August 4, 2018, 8:01pm UTC](https://boards.straightdope.com/t/do-you-know-your-blood-type/818539/72 "2018-08-04T20:01:13Z")
Yes. ---
**Author:** ![RivkahChaya](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/rivkahchaya/32/8919_2.png) [@RivkahChaya](https://boards.straightdope.com/u/RivkahChaya)\ **Post date:** [August 4, 2018, 8:18pm UTC](https://boards.straightdope.com/t/do-you-know-your-blood-type/818539/73 "2018-08-04T20:18:13Z")
> [@Velocity](#): > > Wait, a blood type can make you more susceptible to disease or bad health conditions? Apparently having an O genotype makes you have slightly more gray matter, and that is connected to a lower risk for various forms of dementia. People with O blood have two O genes. People with AB don’t have any. People with A or B blood may or may not have an O gene, and that would explain why on average, people with A or B blood have less gray matter than people with O blood, but more than people with AB blood. The fact is, that people whose genotype is AA or BB have the same risk as people who are AB, but researchers have only very recently teased out this fact, and there is not a whole lot of data yet. Of course, your blood type is not the be-all and end-all. A strong family history of dementia, particularly early-onset is your biggest risk factor. If parents with A & B blood and absolutely no family history on either side produce one O child, and one AB child, the AB child will have an elevated risk over his O sibling, but still a much lesser risk than an unrelated person with O blood who had three out of four grandparents with dementia. At least, that’s how it was explained to me. All disclaimers apply: IANAD, IIRC, etc. ---
**Author:** ![JohnT](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johnt/32/15048_2.png) [@JohnT](https://boards.straightdope.com/u/JohnT)\ **Post date:** [August 4, 2018, 8:32pm UTC](https://boards.straightdope.com/t/do-you-know-your-blood-type/818539/74 "2018-08-04T20:32:33Z")
O- And you can bet the blood and tissue center have me in their crosshairs… ---
**Author:** ![puzzlegal](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/puzzlegal/32/3827_2.png) [@puzzlegal](https://boards.straightdope.com/u/puzzlegal)\ **Post date:** [August 4, 2018, 8:58pm UTC](https://boards.straightdope.com/t/do-you-know-your-blood-type/818539/75 "2018-08-04T20:58:43Z")
B+. It came out B- when I tested it in my high school biology class, but almost the entire class tested rH negative, I’m pretty sure the testing materials were out-dated and didn’t work properly. When I was pregnant I was tested because it potentially mattered, and I trust that test more than the one I did. ---
**Author:** ![RivkahChaya](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/rivkahchaya/32/8919_2.png) [@RivkahChaya](https://boards.straightdope.com/u/RivkahChaya)\ **Post date:** [August 4, 2018, 10:00pm UTC](https://boards.straightdope.com/t/do-you-know-your-blood-type/818539/76 "2018-08-04T22:00:37Z")
> [@CelticKnot](#): > > What’s the incubation period for JK disease? You mean CJD? It can be as long as 12 years. I read a book that discussed people who, as children, had been given cadaver-derived human growth hormone (there is an artificial form now for people deficient in it), and some of them were accidentally exposed to it. No cadavers that died of neurological disorders were used, but a number of “Potter’s field” bodies were, and many of them died of accidents before the disease began to progress at all. ---
**Author:** ![Sveltington](https://avatars.discourse-cdn.com/v4/letter/s/3ab097/32.png) [@Sveltington](https://boards.straightdope.com/u/Sveltington)\ **Post date:** [August 5, 2018, 6:18pm UTC](https://boards.straightdope.com/t/do-you-know-your-blood-type/818539/77 "2018-08-05T18:18:58Z")
yes ---
**Author:** ![Arabella\_Flynn](https://avatars.discourse-cdn.com/v4/letter/a/8491ac/32.png) [@Arabella\_Flynn](https://boards.straightdope.com/u/Arabella_Flynn)\ **Post date:** [August 6, 2018, 12:11am UTC](https://boards.straightdope.com/t/do-you-know-your-blood-type/818539/78 "2018-08-06T00:11:51Z")
Nope! I’m hypotensive and have a worrying tendency to pass out. Nobody wants that in a donor, and if I ever needed a transfusion I’d be too unconscious to tell them anything anyway. ---
**Author:** ![Johanna](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johanna/32/8318_2.png) [@Johanna](https://boards.straightdope.com/u/Johanna)\ **Post date:** [August 6, 2018, 6:28am UTC](https://boards.straightdope.com/t/do-you-know-your-blood-type/818539/79 "2018-08-06T06:28:11Z")
I had an advantage. My mom’s a nurse, so I’ve known for as far back as I can remember. We’re all B positive. ---
**Author:** ![Yllaria](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/yllaria/32/3452_2.png) [@Yllaria](https://boards.straightdope.com/u/Yllaria)\ **Post date:** [August 6, 2018, 5:34pm UTC](https://boards.straightdope.com/t/do-you-know-your-blood-type/818539/80 "2018-08-06T17:34:09Z")
> [@RivkahChaya](#): > > A. . . People with O blood have two O genes. People with AB don’t have any. People with A or B blood may or may not have an O gene, . . . I always thought that you could have A genes and/or B genes and if you had neither, you were O. So that you can’t have an O gene. Saying that someone is AO or BO is just saying that they only have one A or B gene. ---
**Author:** ![Dendarii\_Dame](https://avatars.discourse-cdn.com/v4/letter/d/bbce88/32.png) [@Dendarii\_Dame](https://boards.straightdope.com/u/Dendarii_Dame)\ **Post date:** [August 6, 2018, 6:22pm UTC](https://boards.straightdope.com/t/do-you-know-your-blood-type/818539/81 "2018-08-06T18:22:05Z")
I’m B positive. [Previous page](https://boards.straightdope.com/t/do-you-know-your-blood-type/818539.md?page=3) [Next page](https://boards.straightdope.com/t/do-you-know-your-blood-type/818539.md?page=5)