If a patient gets the wrong blood type, the antibodies immediately set out to destroy the invading cells. This aggressive, whole-body response can give someone a fever, chills, and low blood pressure. It can even cause vital body systems — like breathing or the kidneys — to fail. In the same way, if you have the B marker, your body makes A antibodies. Blood transfusions are one of the most frequent lifesaving procedures hospitals do.
Every 2 seconds someone needs a blood transfusion. So there's always a need for blood donors. One blood donation can save up to three lives. If you'd like to help, contact your community blood center. It's one way to be an everyday superhero and save lives! Reviewed by: Maureen F.
Edelson, MD. Larger text size Large text size Regular text size. What Are the Components of Blood? All blood contains the same basic components: red blood cells white blood cells platelets plasma But not everyone has the same blood type. What Are the Blood Types? The two main blood groups are ABO and Rh. Type B: This blood type has a marker known as B.
Type O: This blood type has neither A or B markers. So, there are eight possible blood types: O negative. In order to comprehend how this can happen, it is necessary to understand some basic immunology. There are two basic types of immune responses: humoral, or antibody-mediated, and cellular. Humoral immune responses result in the production of antibodies that are specific to a foreign antigen. When these antibodies attach to the antigen--on bacteria, for example--immune complexes are formed.
The body's macrophages, mainly in the liver and spleen, then remove and destroy the immune complexes. Once attached to antigens, antibodies can also activate what is known as the complement pathway. As an end result, complement activation can punch holes in the membranes of bacteria or cells that are coated with antibodies.
When red blood cells are the target of antibodies and complement, a condition called hemolysis results. Immune responses evoked by blood transfusion, when they occur, are usually humoral in nature.
Organ and bone marrow transplants, in contrast, usually evoke cellular immune responses, which lead to the production of specific cytotoxic lymphocytes. The most important blood cell antigens in transfusion are in the ABO system. Virtually everyone over the age of six months has antibodies to the A or B antigens that they don't produce. For example, a group A individual has A antigen on his red cells and anti-B in his plasma.
If blood is transfused to a patient who already has antibodies to the transfused cells giving this individual group B blood, for example then a serious reaction can occur. Because antibodies to A and B antigens are good at activating complement, transfusion of ABO incompatible red cells can cause breakdown of the cells in circulation and a strong inflammatory response. The end result can be kidney failure and even death. Fortunately, this type of immediate rejection of transfused red cells is rare.
A more common type of rejection of transfused red cells is a delayed hemolytic reaction. In this case, the patient does not have preexisting antibodies to the transfused red cells. Rather, an immune response occurs days to weeks after the transfusion. The antibodies produced in such reactions tend not to activate complement, so the transfused red cells in circulation do not usually break down.
Instead, the cells are removed by the spleen and a milder inflammatory response may occur. Delayed hemolytic reactions occur in about one out of every 5, transfusions. The antibodies involved can be directed against one or more of hundreds of known blood group antigens.
Delayed hemolytic transfusion reactions usually are not very severe, but sometimes do cause renal failure. Patients with sickle cell anemia are at greater risk of having delayed hemolytic reactions because they often receive many transfusions. These reactions can be more severe than in other patients because the loss of normal hemoglobin containing red cells and the inflammation caused by the reaction can trigger a sickle crisis.
You may have a partial crossmatch if you are in critical need of blood, and your healthcare provider decides that waiting for a full test could be more dangerous for you.
If your situation is too urgent to wait for even a partial crossmatch, type O blood may be used. Type O blood is called the universal donor and has the highest probable compatibility with other blood types.
Test results may vary depending on your age, gender, health history, the method used for the test, and other things. Ask your healthcare provider what your test results mean for you.
This test does not have a "normal" result. The goal of blood typing and crossmatching is to find a compatible blood type for transfusion. The results will tell your healthcare provider what blood or blood components will be safe to give you. If your crossmatch finds no antibodies, you have a very low possibility that your blood type will be incompatible with the donor type.
If your crossmatch comes back positive, it means it's likely that antibodies were found. In this case, the antibodies must be isolated in a lab to find out how significant they are. Not all antibodies cause donor blood to be incompatible with your type. But when they are, using blood from that particular donor will most likely be ruled out. The test is done with a blood sample. A needle is used to draw blood from a vein in your arm or hand. Having a blood test with a needle carries some risks.
These include bleeding, infection, bruising, and feeling lightheaded.
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