Quote from HappyJaxRN
Can someone please explain to me...in layman's terms....What blood anitibodies are. I'm having a brain-toot moment. I had to wait over 5 hours yesterday for 3 units of blood because the blood bank stated that the blood had antibodies and it took longer. I know that there are 3 types of antibodies. A, B, and Rh? Is that right? Please explain if you can. Thanks.
There are two major typing classes. One is the ABO grouping. There are people with the A type, people with B type, people with both and are AB, and people with neither which is classed O, for lack of a better way to class them.
Then there is separate class of typing for the rHesus factor or rH factor, If you have it, you are rH positive. If it is absent, you are rH negative.
In ER, when they ask for Onegative, until they get type specific, the presumption is that O (being non A or B) and rH negative being absent the rH factor, that it will be moderately compatible with everyone. This not necessarily true, but in case of an immediate need, may be done.
People with A, B, or AB blood can receive RBCs, from type O (because they are absent the A or the B. AB people can receive RBCs from O or A or B, as they will not receive any factor that they do not already have. Type O can only receive type O, as anything else would introduce a "foreign factor" into their system.
rH positives can receive from rH negatives but not vice versa.
The most dangerous transfusion reactions are those where the mismatch is within these groups. However, there are other factors that can cause harm if infused into someone sensitive. You may see letters like AntiE, Dnegative, Fnegative, etc. on blood. While the majority of people are not sensitive to these factors, some are. Their transfusion products require special tests done to weed out these unusual factors.
There are even some people that have a cold agglutanin (?) that will have have a lifethreatening reactions to blood unless it is warmed before infusion.
We say that the patient has become "sensitized" or has developed "antibodies" when these precautions must be taken, and cross matches are harder to come by.
Recipients can also have mild reactions such as itching, rash to a transfusion if they have relatively benign incompatibilities with the donor, but some can have seriously lifethreatening ones due sensitization.
These days, with increased filtering, leukoreduction and irradiation of blood to high risk patients (such as Onco/hemo/sickle cell/hemophiliac patients) that receive repeated transfusions, sensitization is becoming less common, but is still a problem, especially in those groups.
Platelets, in particular, pose a problem. A typical platelet transfusion was 6-8 units random donor units (platelets from 6-8 separate donations/donors). Each time a person was infused platelets, their bodies had to deal with numerous "foreign" factors. These days, high risk patients receive 1 pheresis unit - equivalent in amount to 6-8 random units - where the platelets were given by one donor, with their red cells was returned to them - to limit sensitization problems.
Some patients become so sensitized that their body will destroy platelets from any donation, as well destroy its own platelets in response to transfusion. You transfuse platelets and the counts will not increment, or even decrease, in response to transfusion. These patients must receive HLA matched products......very difficult to obtain.
I have used "factor" instead of antibodies or antigens...because I always mix them up in typing (no pun intended) but maybe this explains what you are seeing, perhaps.