What happens if two blood types are mixed

When RhD is present on the red cell surface, the red cells are called RhD positive. Antibodies to RhD develop only after an individual is exposed to RhD antigens via transfusion, pregnancy or organ transplantation. Anti RhD or anti-D antibodies destroy RhD positive red cells and can lead to haemolytic transfusion reactions.

This is of particular importance in pregnancy where anti-D antibodies can cross the placenta from mother to unborn child and lead to haemolytic disease of the newborn. As a general rule, RhD negative individuals should not be transfused with RhD positive red cells, especially RhD negative girls and women of childbearing age. If transfusion of an RhD positive product to RhD negative recipient is unavoidable a haematologist should be consulted and administration of anti-D immunoglobulin considered.

When a transfusion is given, it is preferable for patients to receive blood and plasma of the same ABO and RhD group. However if the required blood type is unavailable, a patient may be given a product of an alternative but compatible group as shown below. Blood Compatibility. Patient Type. Compatible Red Cell Types. O RhD negative red cells are issued in emergency situations where life saving transfusion is required prior to completion of a crossmatch. Click here for further information on emergency blood release.

Group O is often referred to as the universal red cell donor. Group AB individuals have neither anti-A nor anti-B antibodies in their plasma. Group AB plasma can therefore be given to patients of any ABO blood group and is often referred to as the universal plasma donor. In: Rifai N, ed. St Louis, MO: Elsevier; chap Nester T. Blood component therapy and transfusion reactions. Conn's Current Therapy Philadelphia, PA: Elsevier; Review provided by VeriMed Healthcare Network.

Editorial team. ABO incompatibility. Due to modern testing techniques, this problem is very rare. The different blood types are: Type A Type B Type AB Type O People who have one blood type may form proteins antibodies that cause their immune system to react against one or more of the other blood types.

People with type B blood will react against type A or type AB blood. The following are symptoms of ABO incompatible transfusion reactions : Low back pain Blood in urine Chills Feeling of "impending doom" Fever Nausea and vomiting Shortness of breath Increased heart rate Pain at infusion site Chest pain Dizziness Bronchospasm spasm of the muscles lining the lung; causes cough Yellow skin and whites of the eyes jaundice Acute kidney failure Low blood pressure Disseminated intravascular coagulation DIC.

Exams and Tests. The health care provider will perform a physical exam. Blood tests will usually show: The bilirubin level is high The complete blood count CBC shows damage to red blood cells or anemia The recipient's and donor's blood are not compatible Elevated lactate dehydrogenase LDH Elevated blood urea nitrogen BUN and creatinine ; in case of renal injury Prolonged prothrombin time or partial thromboplastin time findings of DIC Positive direct antiglobulin test DAT Urine tests show the presence of hemoglobin due to breakdown of red blood cells.

Do you want to know why? This post explains it all:. Blood is considered a tissue and consists mainly of red blood cells, platelets, and white blood cells. Up until that point, some human to human blood transfusions had been proven to be successful and others not, but the reason was unknown.

Consequently, he discovered three different types of red blood cell antigens: A, B and O , a finding for which he later received the Nobel Prize. The ABO gene has three alleles: A, B and O, and the blood type is determined by the presence or absence of these 3 alleles. An allele is each of the forms in which the same gene can be expressed. As previously outlined, the different blood groups are determined by the absence or presence of certain antigens in the red blood cells.

These antigens vary depending on what alleles they comprise. Like the ABO system, the Rh Rhesus system, also called the D antigen , is based on the absence or presence of a certain antigen on the red blood cell membrane surface:. Not all blood groups are compatible with each other, there is specific compatibility for both the ABO group and the Rh factor. The table below illustrates the compatibility of different blood groups for receiving and donating blood:. This is because the immune reaction that is triggered causes the breakdown of red blood cells haemolysis.

Rh positive is the most common blood group. Rh negative is less common, and certain precautions must be taken with Rh negative women when pregnant. If their partner is Rh positive, there is a possibility that the baby will also be Rh positive, which may lead to complications during pregnancy. This occurs if the blood of the mother and child come into contact.

This is usually not a problem in a first pregnancy, but it can be a problem in later pregnancies, as antibodies could penetrate the placenta and attack the red blood cells of a future Rh-positive baby. This could cause anaemia in the foetus that could kill it.

At the first prenatal consultation, the doctor will request a blood group and Rh factor test for the mother. If you are Rh negative, you will probably have an antibody test in the first trimester to detect possible Rh positive antibodies and, if necessary, take further action with anti-D gamma globulin injections. Here, blood plasma without cells is mixed with type A or type B blood:.