# Blood Transfusion Question **URL:** \ **Category:** Factual Questions\ **Created:** [July 20, 2002, 7:54pm UTC](https://boards.straightdope.com/t/blood-transfusion-question/120004 "2002-07-20T19:54:02Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![Daoloth](https://avatars.discourse-cdn.com/v4/letter/d/82dd89/32.png) [@Daoloth](https://boards.straightdope.com/u/Daoloth)\ **Post date:** [July 20, 2002, 7:54pm UTC](https://boards.straightdope.com/t/blood-transfusion-question/120004/1 "2002-07-20T19:54:02Z")
What if someone received a transfusion of incompatible blood? (i.e., type O receiving type B) What would happen? ---
**Author:** ![Lsura](https://avatars.discourse-cdn.com/v4/letter/l/7993a0/32.png) [@Lsura](https://boards.straightdope.com/u/Lsura)\ **Post date:** [July 20, 2002, 7:58pm UTC](https://boards.straightdope.com/t/blood-transfusion-question/120004/2 "2002-07-20T19:58:26Z")
From [here](http://sln.fi.edu/biosci/blood/types.html) > [@](#): > > If two different blood types are mixed together, the blood cells may begin to clump together in the blood vessels, causing a potentially fatal situation. Therefore, it is important that blood types be matched before blood transfusions take place. In an emergency, type O blood can be given because it most likely to be accepted by all blood types. However, there is still a risk involved. ---
**Author:** ![Lsura](https://avatars.discourse-cdn.com/v4/letter/l/7993a0/32.png) [@Lsura](https://boards.straightdope.com/u/Lsura)\ **Post date:** [July 20, 2002, 8:01pm UTC](https://boards.straightdope.com/t/blood-transfusion-question/120004/3 "2002-07-20T20:01:11Z")
Found another link that indicates the “clumping” has to do with [antibodies](http://www.mckinley.uiuc.edu/health-info/hlthpro/bloodtyp.html) > [@](#): > > WHAT IS A BLOOD TYPE? > When your practitioner tells you your “blood type,” you are being given two pieces of information - your blood group and your Rh status. > > a. Your blood group will be A, B, AB, or O. If you have “A” “B” or “O” blood group, you have antibodies in your blood plasma that destroy some of the other blood groups. If you have group “A” blood, you cannot receive blood that is group “B” and vice versa. If you have “O” blood, your body will create antibodies to fight “A” or “B” blood. If you have group “AB” blood however, your body will not create antibodies for any of the other blood groups. > > b. Your Rh status will be listed as negative (-) or positive (+). If you have Rh- blood, your body may form antibodies against Rh+ blood and destroy it. In order for this to happen, you must first be exposed to Rh+ blood (i.e., through a blood tranfusion or carrying an Rh+ fetus). This can be a problem if you have antibodies against Rh+ blood and are pregnant with an Rh+ fetus. However, there is medication that can prevent this reaction from occurring if it is given immediately after you are exposed to Rh+ blood. ---
**Author:** ![Qadgop\_the\_Mercotan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/qadgop_the_mercotan/32/83_2.png) [@Qadgop\_the\_Mercotan](https://boards.straightdope.com/u/Qadgop_the_Mercotan)\ **Post date:** [July 20, 2002, 8:03pm UTC](https://boards.straightdope.com/t/blood-transfusion-question/120004/4 "2002-07-20T20:03:43Z")
To be a bit more explicit, those blood clots formed by a transfusion reaction with incompatable blood will form in places like the brain, kidneys, lungs, liver, etc. causing tremendous pain and dysfunction before death. ---
**Author:** ![mnemosyne](https://avatars.discourse-cdn.com/v4/letter/m/c4cdca/32.png) [@mnemosyne](https://boards.straightdope.com/u/mnemosyne)\ **Post date:** [July 21, 2002, 5:52pm UTC](https://boards.straightdope.com/t/blood-transfusion-question/120004/5 "2002-07-21T17:52:09Z")
_shudder_ Now I’m glad I’m AB+ and don’t really have to worry about any of it, in case I ever need a transfusion 🙂 ---
**Author:** ![WV\_Woman](https://avatars.discourse-cdn.com/v4/letter/w/e95f7d/32.png) [@WV\_Woman](https://boards.straightdope.com/u/WV_Woman)\ **Post date:** [July 21, 2002, 9:46pm UTC](https://boards.straightdope.com/t/blood-transfusion-question/120004/6 "2002-07-21T21:46:42Z")
Remember when you were a kid and you had to sign those little emergency forms when you went on a field trip in case you got in some kinda icky school bus crash or something? My (nurse) aunt tells me that these days hospitals won’t even take your word for it re: your blood type. Unless you are absolutely pounding at death’s door (in which case they would immediately give you O- blood), they’re gonna test your blood to confirm your blood type before they give you a transfusion. ---
**Author:** ![KarlGauss](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/karlgauss/32/3713_2.png) [@KarlGauss](https://boards.straightdope.com/u/KarlGauss)\ **Post date:** [July 22, 2002, 12:23am UTC](https://boards.straightdope.com/t/blood-transfusion-question/120004/7 "2002-07-22T00:23:35Z")
[clarification] When a type O person receives type A, B, or AB blood, he/she will experience a \*\*\*hemolytic \*\*\*transfusion reaction. As mentioned, people who are blood type O have naturally occurring antibodies to type A (and type B) red blood cells. These antibodies will lyse (break apart) the transfused incompatible red blood cells **by signaling a group of substances called _complement_ to disrupt the red cells’ membranes**. When large numbers of red blood cells lyse in the circulation (such as occurs in a hemolytic transfusion reaction), and when the complement system is activated, a syndrome ensues characterized by kidney failure, lung failure, agonizing pain, and even death. To a large extent, this syndrome occurs because complement activation activates, in turn, the coagulation system and the inflammatory system. The result is systemic (widespread) clotting and inflammation. Not good. [/clarification]