Blood Groups, Blood Typing and Blood Transfusions Blood Groups, Blood Typing and Blood Transfusions The discovery of blood groups Experiments with blood transfusions, the transfer of blood or blood components into a person's blood stream, have been carried out for hundreds of years. Many patients have died and it was not until 1901, when the Austrian Karl Landsteiner discovered human blood groups, that blood transfusions became safer. Mixing blood from two individuals can lead to blood clumping or agglutination. The clumped red cells can crack and cause toxic reactions. This can have fatal consequences. Karl Landsteiner discovered that blood clumping was an immunological reaction which occurs when the receiver of a blood transfusion has antibodies against the donor blood cells. Karl Landsteiner's work made it possible to determine blood groups and thus paved the way for blood transfusions to be carried out safely. For this discovery he was awarded the Nobel Prize in Physiology or Medicine in 1930. What is blood made up of? An adult human has about 4–6 liters of blood circulating in the body. Among other things, blood transports oxygen to various parts of the body.

Blood consists of several types of cells floating around in a fluid called plasma. The red blood cells contain hemoglobin, a protein that binds oxygen. Red blood cells transport oxygen to, and remove carbon dioxide from, the body tissues. The white blood cells fight infection. The platelets help the blood to clot, if you get a wound for example. The plasma contains salts and various kinds of proteins. What are the different blood groups? The differences in human blood are due to the presence or absence of certain protein molecules called antigens and antibodies. The antigens are located on the surface of the red blood cells and the antibodies are in the blood plasma. Individuals have different types and combinations of these molecules. The blood group you belong to depends on what you have inherited from your parents. There are more than 20 genetically determined blood group systems known today, but the AB0 and Rh systems are the most important ones used for blood transfusions. Not all blood groups are compatible with each other. Mixing incompatible blood groups leads to blood clumping or agglutination, which is dangerous for individuals.

Nobel Laureate Karl Landsteiner was involved in the discovery of both the AB0 blood group (in 1901) and Rh blood group (in 1937). AB0 blood grouping system According to the AB0 blood group system there are four different kinds of blood groups: A, B, AB or 0 (null). Blood group A If you belong to the blood group A, you have A antigens on the surface of your red blood cells and B antibodies in your blood plasma. Blood group B If you belong to the blood group B, you have B antigens on the surface of your red blood cells and A antibodies in your blood plasma. Blood group AB If you belong to the blood group AB, you have both A and B antigens on the surface of your red blood cells and no A or B antibodies at all in your blood plasma. Blood group 0 If you belong to the blood group 0 (null), you have neither A or B antigens on the surface of your red blood cells but you have both A and B antibodies in your blood plasma. Rh factor blood grouping system Many people also have a so called Rh factor on the red blood cell's surface.

This is also an antigen and those who have it are called Rh+. Those who haven't are called Rh-. A person with Rh- blood does not have Rh antibodies naturally in the blood plasma (as one can have A or B antibodies, for instance). But a person with Rh- blood can develop Rh antibodies in the blood plasma if he or she receives blood from a person with Rh+ blood, whose Rh antigens can trigger the production of Rh antibodies. A person with Rh+ blood can receive blood from a person with Rh- blood without any problems. Blood group notation According to above blood grouping systems, you can belong to either of following 8 blood groups: A Rh+ Do you know which blood group you belong to? Blood typing – how do you find out to which blood group someone belongs? 1. You mix the blood with three different reagents including either of the three different antibodies, A, B or Rh antibodies. 2. Then you take a look at what has happened. In which mixtures has agglutination occurred? The agglutination indicates that the blood has reacted with a certain antibody and therefore is not compatible with blood containing that kind of antibody.

If the blood does not agglutinate, it indicates that the blood does not have the antigens binding the special antibody in the reagent. 3. If you know which antigens are in the person's blood, it's easy to figure out which blood group he or she belongs to! A person with A+ blood receives B+ blood. The B antibodies (yellow) in the A+ blood attack the foreign red blood cells by binding to them. The B antibodies in the A+ blood bind the antigens in the B+ blood and agglutination occurs. This is dangerous because the agglutinated red blood cells break after a while and their contents leak out and become toxic. What happens when blood clumps or agglutinates? For a blood transfusion to be successful, AB0 and Rh blood groups must be compatible between the donor blood and the patient blood. If they are not, the red blood cells from the donated blood will clump or agglutinate. The agglutinated red cells can clog blood vessels and stop the circulation of the blood to various parts of the body. The agglutinated red blood cells also crack and its contents leak out in the body.

The red blood cells contain hemoglobin which becomes toxic when outside the cell. This can have fatal consequences for the patient. The A antigen and the A antibodies can bind to each other in the same way that the B antigens can bind to the B antibodies. This is what would happen if, for instance, a B blood person receives blood from an A blood person. The red blood cells will be linked together, like bunches of grapes, by the antibodies. As mentioned earlier, this clumping could lead to death. Blood transfusions – who can receive blood from whom? Of course you can always give A blood to persons with blood group A, B blood to a person with blood group B and so on. But in some cases you can receive blood with another type of blood group, or donate blood to a person with another kind of blood group. The transfusion will work if a person who is going to receive blood has a blood group that doesn't have any antibodies against the donor blood's antigens. But if a person who is going to receive blood has antibodies matching the donor blood's antigens, the red blood cells in the donated blood will clump.

People with blood group 0 Rh - are called "universal donors" and people with blood group AB Rh+ are called "universal receivers." Rh+ blood can never be given to someone with Rh - blood, but the other way around works. For example, 0 Rh+ blood can not be given to someone with the blood type AB Rh -. Blood Groups and Blood Types About Watch and Favorite Watch Watching this resources will notify you when proposed changes or new versions are created so you can keep track of improvements that have been made. Favorite Favoriting this resource allows you to save it in the “My Resources” tab of your account. There, you can easily access this resource later when you’re ready to customize it or assign it to your students. Blood Groups and Blood Types Red blood cells have surface-expressed proteins that define the self/not-self nature of the cells. Learning Objective Evaluate the ABO and Rhesus blood groups in terms of donors and recipients Key Points Surface-expressed proteins called antigens on red blood cells determine an individual's blood type. There are two types of antigen groups: the ABO system antigens and a Rhesus D antigen.

Exposure to a blood group antigen that is not recognized as self will cause the immune system to make specific antibodies to the new blood group antigen, often leading to destruction of the cells. Knowing an individual's antigen type is important to ensure compatibility if a transfusion is needed. Blood type is inherited. O type is the most common despite being a recessive gene because it is more highly expressed in the gene pool, while type A and type B are dominant (and type AB is codominant) but are less common because they are less expressed in the gene pool. Individuals may also be positive or negative for the rhesus D antigen in addition to their blood type. Rhesus D complications are common during fetal development if the parents differ in rhesus antigen expression. Terms Register for FREE to remove ads and unlock more features! Learn more Full Text Red blood cells have surface-expressed proteins that act as antigens, which are molecules that can illicit an immune system response. Red blood cells belong to different groups on the basis of the type of antigen that they express. Blood type determines compatibility for receiving blood transfusions from other people.

The ABO Blood Group System If an individual is exposed to a blood group antigen (A or B) that is not recognized as self, the individual can become sensitized to that antigen. This will cause the immune system to make specific antibodies to a particular blood group antigen and form an immunological memory against that antigen. These antibodies can bind to antigens on the surface of transfused red blood cells (or other foreign tissue cells), often leading to destruction of the cells by recruitment of other components of the immune system. Knowledge of an individual's blood type is important to identify appropriate blood for transfusion or tissue for organ transplantation . There are four blood types that differ based on the antigen expressed by the red blood cell and by the type of associated antibody found in the plasma . The type of antigen determines which blood types that blood type may safely be donated to, while the type of antibody determines which types of antigen (and types of blood) will be rejected by the body. This chart depicts blood type classification. Group A has a red blood cell type A, plasma antibody of anti-B, red blood cell antigen A. Group A has a red blood cell type B, plasma antibody of anti-A, red blood cell antigen B.

Group AB has a red blood cell type AB, no plasma antibody, red blood cell antigens A and B. Group O has a red blood cell type ), plasma antibodies of anti-A and anti-B, no red blood cell antigen. Blood group A individuals have the A antigen on the surface of their RBCs, and blood serum containing IgM antibodies against the B antigen. Therefore, a group A individual can only receive blood from individuals of groups A or O types, and can donate blood to individuals of groups A or AB. Blood group B individuals have the B antigen on their surface of their RBCs, and blood serum containing IgM antibodies against the A antigen. Therefore, a group B individual can only receive blood from individuals of groups B or O, and can donate blood to individuals of groups B or AB. Blood Group AB individuals have both A and B antigens on the surface of their RBCs, and their blood serum does not contain any antibodies against either A or B antigen. Therefore, an individual with type AB blood can receive blood from any group, but can only donate blood to another group AB individual. AB blood is also known as "universal receiver.

" Blood group O individuals do not have either A or B antigens on the surface of their RBCs, but their blood serum contains IgM antibodies against both A and B antigens. Therefore, a group O individual can only receive blood from a group O individual, but they can donate blood to individuals of any ABO blood group (i.e. A, B, O, or AB). O blood is also known as "universal donor. " Blood types are inherited and represent genetic contributions from both parents. The gene that codes for blood type contains three alelles: IA and IB which give type A and B blood and are dominant, and i, which is recessive and codes type O. Children will have blood types similar to their parents based on inheritance. The i allele is far more commonly expressed in the gene pool than IA and IB, which is why type O blood is the most common type despite being a recessive phenotype. Type AB is the rarest because it is the combination of less commonly expressed alleles, and is the result of codominance between IA and IB alelles. Rhesus Factor Many people also have the rhesus D (Rh) antigen expressed by their red blood cells.

Those that are have Rh antigens are positive for Rh, while those that don't have it are Rh negative (ie. type O+ is type O with rhesus, type A- is type A without rhesus). Rh positive individuals do not have the antibodies for the Rh factor, but can make them if exposed to Rh. Besides being a consideration for blood transfusion, parents who differ based on Rh status must be cautious to ensure that maternal antibodies do not destroy their child's red blood cells during fetal development, which can cause hemolytic anemia . Blood Types Chart | Blood Group Information | American Red Cross Printable Version Blood Types Although all blood is made of the same basic elements, not all blood is alike. In fact, there are eight different common blood types, which are determined by the presence or absence of certain antigens – substances that can trigger an immune response if they are foreign to the body. Since some antigens can trigger a patient's immune system to attack the transfused blood, safe blood transfusions depend on careful blood typing and cross-matching.

The ABO Blood Group System There are four major blood groups determined by the presence or absence of two antigens – A and B – on the surface of red blood cells: Group A – has only the A antigen on red cells (and B antibody in the plasma) Group B – has only the B antigen on red cells (and A antibody in the plasma) Group AB – has both A and B antigens on red cells (but neither A nor B antibody in the plasma) Group O – has neither A nor B antigens on red cells (but both A and B antibody are in the plasma) There are very specific ways in which blood types must be matched for a safe transfusion. See the chart below: In addition to the A and B antigens, there is a third antigen called the Rh factor, which can be either present (+) or absent ( – ). In general, Rh negative blood is given to Rh-negative patients, and Rh positive blood or Rh negative blood may be given to Rh positive patients. The universal red cell donor has Type O negative blood type. The universal plasma donor has Type AB blood type. Blood Types and the Population O positive is the most common blood type. Not all ethnic groups have the same mix of these blood types.

Hispanic people, for example, have a relatively high number of O’s, while Asian people have a relatively high number of B’s. The mix of the different blood types in the U.S. population is: Blood Types, Facts, and Donation Health Information Provided by Health Testing Centers Date Published: February 9, 2012 Author: Karen Alton, LPN Blood Types, Facts, and Donation Everyone, regardless of age, gender or ethnicity, relies on blood to survive. As a result there is a constant need for all blood types. The available supply of blood is dependent on donations made by eligible individuals throughout the country. There is however, often a fear that is associated with the act of donating blood. Education is the best way to promote blood donation, overcome any fears about the process and help maintain the blood supply at a level that meets the current need. Blood Types The ABO Blood Group System Blood is categorized in four primary types, or groups, based off of the ABO system. The four potential blood types are A, B, AB, and O. Antigens that are on the surface of red blood cells are either type A or they are type B.

Their presence, or absence, determines whether blood is a type A or B. Blood groups are determined based off of these antigens. Blood types must be accurately matched for a safe red blood cell transfusion. People with type O blood can donate to all blood types and people with type A blood can donate to people with type A and type AB. A person with type B blood can safely donate to people with type B and type AB. If a person has type AB blood, he may donate red cells only to others with type AB. The presence of the Rh protein, or factor, in blood also helps determine a person’s blood type. The Rh factor is another type of antigen that may or may not be present in the blood. If it is present, the blood type is positive. If the Rh protein is absent, it is negative. Type O negative blood is the universal red cell donor. This means that a person that is O negative can donate his blood to anyone regardless of that person’s blood type. Type AB positive is the universal plasma donor. This means that a person with this blood type can donate blood to anyone. Blood Types and Population Not all ethnic groups have the same percentage of blood type combinations. The mix of blood types varies by ethnic group.

At two percent, Hispanics have the lowest percentage of AB positive. Asians, at seven percent, have the highest percent of AB positive blood types. Hispanics have the highest percentage of O positive blood at 53 percent. Caucasians have the lowest percentage of O positive blood. Overall, the most common blood type is O positive. Matching both ethnic background and ABO blood type can at times provide a closer blood match. This can reduce the chance of a reaction in some cases and help in the treatment of certain ethnic specific conditions, such as sickle cell disease. How is My Blood Type Determined? A person's blood type is determined by a combination of two genes, one from each parent. Blood typing is not enough to determine paternity. A child whose parents both are type A, the child will potentially be a type A or a type O. If both parents are a type B, than he will be either a type B or an O. When one parent is a type A and the other a type B, the child may have any of the four blood types. When one parent is a type AB and the second parent is either AB, A, or B, the child will be a type AB, A or B.

Blood Facts and Statistics Facts About Blood Needs Diseases such as sickle cell and cancer require blood transfusions. Cancer patients may require transfusions on a daily basis. The amount of red blood cells needed for a transfusion is three pints. In the United States, blood is needed every two seconds. To meet the need for blood, there must be 38,000 blood donations daily. Victims of car accidents may require as much as 100 pints of blood on average. Facts About the Blood Supply At present, there is no way that blood can be manufactured. It can only be collected by donors. There are roughly five million patients that receive blood yearly. There are 9.5 million blood donors in the United States. Less than 38 percent of people living in the United States are eligible to give blood. In the United States, 16 million donations of blood are collected in a year. Facts About the Blood Donation Process Sterile needles used to collect blood are single use only. Before releasing donated blood to hospitals, it is tested for infectious diseases, such as Human Immunodeficiency Virus (HIV), hepatitis B and C and syphilis.

Red blood cells may be donated every 56 days. When double red cells are donated, there must be 112 days between donations. Platelets may be donated up to 24 times a year. Seven days must pass between donations. The donation process takes an hour and 15 minutes. The portion of this process that involves having the blood drawn for donation takes no more than 12 minutes. Facts About Blood and Its Components A single blood donation can save three lives. This is because up to three transfusable components are taken from a pint of donated blood. These components, red cells, platelets, cryoprecipitate and plasma, are derived from blood. Apheresis is a process in which donors can donate blood components only. Red blood cells have a shelf life of 42 days following donation. Platelets are outdated after five days. Red cells, platelets and plasma are replenished by healthy bone marrow. Facts About Donors In the United States, seven percent of people have O negative blood type. When a person's blood type is unknown in emergency situations, O negative is used. In the U.S., only three percent of the population has blood that's type AB.

The percentage of people in the United States with type O blood that's either positive or negative is 45 percent. Both men and women donate blood equally. Facts About American Red Cross Blood Services Forty percent of the blood supply in the United States comes from the Red Cross. The American Red Cross and its sponsors hold over 200,000 blood drives yearly. Approximately 3,000 hospitals in the United States receive blood from the Red Cross. Twenty percent of donated blood comes from Red Cross donor centers, while 80 percent comes from mobile blood drives at various locations. What Happens to Donated Blood? Step One: The Donation Process The donor completes the registration process. The donor provides a medical history and undergoes a mini physical examination. Blood is donated. The Red Cross collects several test tubes and one pint of blood from the donor. Identical barcoded labels are placed on the donor's record, the bag and test tubes of blood. The donated blood is placed in coolers of ice where it is kept until it is taken to the Red Cross Center. Step Two: Processing Procedure The test tubes are sent to be tested. The Red Cross scans the blood donation into its database.

The donated blood is placed in a centrifuge and spun to separate the transfusable components. The Red Cross then leukocyte-reduces the red cells. Platelets are also leukocyte-reduced and they are bacterially tested. Step Three: Testing Process There are five Red Cross National Testing Laboratories. The test tubes are sent to and then received by one of these laboratories. Each unit of blood undergoes a dozen tests. These tests are checking for infectious diseases and are meant to establish the blood type. Within 24 hours, results of the tests are electronically sent to the manufacturing facility. The donor is notified if the tests return positive for infectious diseases. The donated blood is discarded. The testing in this step occurs at the same time as Step two. Step Four and Five: Storage and Distribution Labels are placed on units of blood that undergone testing and are found to be safe. Refrigerators that are kept at six degrees Celsius are used for storing red cells. Red cells are stored for 42 days only. Agitators are used to store platelets at room temperature. They are kept for no longer than five days. Freezers are used to freeze and store plasma and cryo for one year.

Shipping of blood can occur at any time, seven days a week and at any hour. Blood Types: ABO System, Rh System, and Minor Blood Types Credits Your blood is typed, or classified, according to the presence or absence of certain markers ( antigens ) found on red blood cells and in the plasma that allow your body to recognize blood as its own. If another blood type is introduced, your immune system recognizes it as foreign and attacks it, resulting in a transfusion reaction. ABO blood type system The ABO system consists of A, B, AB, and O blood types. People with type A have antibodies in the blood against type B. People with type B have antibodies in the blood against type A. People with AB have no anti-A or anti-B antibodies. People with type O have both anti-A and anti-B antibodies. People with type AB blood are called universal recipients, because they can receive any of the ABO types. People with type O blood are called universal donors, because their blood can be given to people with any of the ABO types. Mismatches with the ABO and Rh blood types are responsible for the most serious, sometimes life-threatening, transfusion reactions. But these types of reactions are rare.

For every 1 million units of blood transfused, getting the wrong blood type happens, at the most, 4 times. 1 Transfusion with the wrong blood type can cause a severe reaction that may be life-threatening. 2 Rh system The Rh system classifies blood as Rh-positive or Rh-negative, based on the presence or absence of Rh antibodies in the blood. People with Rh-positive blood can receive Rh-negative blood, but people with Rh-negative blood will have a transfusion reaction if they receive Rh-positive blood. Transfusion reactions caused by mismatched Rh blood types can be serious. Minor blood types There are over 100 other blood subtypes. Most have little or no effect on blood transfusions, but a few of them may be the main causes of mild transfusion reactions. Mild transfusion reactions are frightening, but they are rarely life-threatening when treated quickly. WebMD Medical Reference from Healthwise This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.© 1995-2015 Healthwise, Incorporated. Healthwise, Healthwise for every health decision, and the Healthwise logo are trademarks of Healthwise, Incorporated.

Next Article Human Blood: ABO Blood Types (1868-1943) The most well-known and medically important blood types are in the ABO group. They were discovered in 1900 and 1901 at the University of Vienna by Karl Landsteiner in the process of trying to learn why blood transfusions sometimes cause death and at other times save a patient. In 1930, he belatedly received the Nobel Prize for his discovery of blood types. All humans and many other primates can be typed for the ABO blood group. There are four principal types: A, B, AB, and O. There are two antigens and two antibodies that are mostly responsible for the ABO types. The specific combination of these four components determines an individual's type in most cases. The table below shows the possible permutations of antigens and antibodies with the corresponding ABO type ("yes" indicates the presence of a component and "no" indicates its absence in the blood of an individual). It is easy and inexpensive to determine an individual's ABO type from a few drops of blood. A serum containing anti-A antibodies is mixed with some of the blood.

Another serum with anti-B antibodies is mixed with the remaining sample. Whether or not agglutination occurs in either sample indicates the ABO type. It is a simple process of elimination of the possibilities. For instance, if an individual's blood sample is agglutinated by the anti-A antibody, but not the anti-B antibody, it means that the A antigen is present but not the B antigen. Therefore, the blood type is A. Genetic Inheritance Patterns Research carried out in Heidelberg, Germany by Ludwik Hirszfeld and Emil von Dungern in 1910 and 1911 showed that the ABO blood types are inherited. We now know that they are determined by genes on chromosome 9, and they do not change as a result of environmental influences during life. An individual's ABO type results from the inheritance of 1 of 3 alleles (A, B, or O) from each parent. The possible outcomes are shown below: The possible ABO alleles for one parent are in the top row and the alleles of the other are in the left column. Offspring genotypes OO (O) Both A and B alleles are dominant over O.

As a result, individuals who have an AO genotype will have an A phenotype . People who are type O have OO genotypes. In other words, they inherited a recessive O allele from both parents. The A and B alleles are codominant. Therefore, if an A is inherited from one parent and a B from the other, the phenotype will be AB. Agglutination tests will show that these individuals have the characteristics of both type A and type B blood. CAUTION: the inheritance of ABO blood types does not always follow such straightforward rules of inheritance. If you wish to explore the reason why this is true, select the Bombay Phenotype button below. Bombay Phenotype ABO Blood type antigens are not only found on the surface of red cells. They are also normally secreted by some people in their body fluids, including saliva, tears, and urine. Whether someone is able to secrete them is genetically controlled. Police agencies now routinely use this so-called secretor system data to identify potential victims and criminals when blood samples are not available. Despite the fact that the blood types of children are solely determined by inheritance from their parents, paternity in the U.S.

and many other nations can no longer be legally established based on conventional blood typing. To do that, it is necessary to compare HLA types and/or DNA sequences. The use of DNA is more accurate in determining paternity, but it is also more expensive than HLA typing. Antibodies to alien antigens in the ABO group are usually present in our plasma prior to the first contact with blood of a different ABO type. This may be partly explained by the fact that these antigens are also produced by certain bacteria and possibly some plants. When we come in contact with them, our bodies may develop long-term active immunity to their antigens and subsequently to the same antigens on the surface of red blood cells. This usually occurs in babies within the first six months following their birth. Environmental Factors While blood types are 100% genetically inherited, the environment potentially can determine which blood types in a population will be passed on more frequently to the next generation. It does this through natural selection . Specific ABO blood types are thought to be linked with increased or decreased susceptibility to particular diseases. For instance, individuals with type A blood are at a somewhat higher risk of contracting smallpox and developing cancer of the esophagus, pancreas, and stomach.

People who are type O are at a higher risk for contracting cholera and plague as well as developing duodenal and peptic ulcers. Research suggests that they are also more tasty to mosquitoes. That could be a significant factor in contracting malaria. NOTE: A small number of people have two different ABO blood types. They are not simply AB codominant. Apparently, most of these blood chimera individuals shared a blood supply with their non-identical twin before birth. In some cases, people are unaware that they had a twin because he or she died early in gestation and was spontaneously aborted. As many as 8% of non-identical twins may have chimeric blood. Some people are microchimeric--they have a small amount of blood of a different type in their system that has persisted from a blood transfusion or passed across the placental barrier from their mother before birth. Likewise, fetal blood can pass into a mother's system. This fact has led some researchers to suggest that the significantly higher frequency of autoimmune disorders in women is a result of the presence of foreign white blood cells that had come from their unborn children during pregnancy.

NEWS: An international team of researchers led by Henrick Clausen of the University of Copenhagen, Denmark have discovered a bacterial enzyme that can convert red blood cells of types A, B, and AB into O by stripping away their identifying surface antigens. This has the potential for dramatically improving the safety of blood transfusions. Clinical trials of this technique are now underway. ("Bacterial Glycosidases for the Production of Universal Red Blood Cells", published online in Nature Biotechnology, April 1, 2007.) NEWS: A research team led by Peer Bork of the European Molecular Biology Laboratory in Heidleberg, Germany discovered that people can be classified into one of 3 distinct types based on the kinds of bacteria in their guts. They refer to them as enterotypes. This type system is independent of blood types and may have equally important implications for peoples' health. How enterotypes are established is not known, but the authors suggest that babies may be randomly colonized by different species of bacteria and that they alter the gut so that only certain species of bacteria can live there. ("Enterotypes of the Human Gut Microbiome", published online in Nature, April 20, 2011.) What are blood types (blood groups)?

- Health questions - NHS Choices What are blood types (blood groups)? What are blood types (blood groups)? People have different types of blood, known as blood groups . The two main systems for classifying blood groups are: the ABO blood group system the Rh system How are blood groups determined? Your blood group is determined by genes that you inherit from your parents. It depends on substances in your blood: antigens – proteins found on the surface of red blood cells that cause antibodies to be produced antibodies – infection-fighting proteins found in plasma (the liquid part of blood) that are part of your immune system and attack specific antigens if they're found in your body The ABO system Under this system, your blood may belong to one of four groups: A – you have A antigens on your red blood cells and anti-B antibodies (antibodies that attack B antigens) B – you have B antigens and anti-A antibodies AB – you have A and B antigens and no anti-A or anti-B antibodies O – you have no antigens, but both anti-A and anti-B antibodies Group O is the most common blood type in the UK.

The Rh system Blood groups | Blood Donation Blood groups Blood groups The most important blood groups in transfusion are the ABO blood group system and the group D of the Rh system. Blood groups or antigens are determined by either sugars or proteins on the surface of the red blood cell. The ABO system has A and B antigens and the Rh system has many antigens but D is the most important. There are 35 blood group systems. This means a person who is A Rh D positive may also be K positive (Kell system), M and N positive (MNS system) and Fya positive but Fyb negative (Duffy system) and so on. The ABO blood group system If you have blood group A then you have got the A antigen on your red cells. Blood group B means you have the B antigen, while group O has neither, and group AB has both A and B antigens. Group O has neither A nor B antigens on the surface of their red cells so red cells of this group can be given safely to any other group. This is why group O donors are known as 'universal red cell donors. Group O makes both anti-A and anti-B antibodies.

The ABO system has associated anti-A and anti-B antibodies, antibodies being the body’s natural defence against foreign antigens. These antibodies are found in the plasma and are unusual in that they are ‘naturally occuring’ so they don’t need to be stimulated – such as by having a transfusion or during pregnancy. This means that blood from someone with blood group A contains anti-B antibodies. Similarly, blood from someone with blood group B contains anti-A antibodies and those with group O contain both anti-A and anti-B whilst those with group AB have neither anti-A nor anti-B. Giving someone blood from the wrong ABO group could be life-threatening. For instance, the anti-A antibodies in a recipient with group B blood group will attack the group A cells if this transfused to them. This is why group A blood must never be given to a group B person. The Rh system Another important blood group system in transfusion is the Rh system. There are 5 main Rhesus (Rh) antigens on red cells – C, c, D, E, e. The most important of these is the Rh D group.

The D antigen on the red cell is what gives you the positive (+) or the negative (-) after the letter A, B, AB or O. It is the most immunogenic and most likely to cause a transfusion reaction in the recipient. To prevent transfusion reactions and production of alloantibody, Rh D negative girls and women of child bearing potential should not be transfused with Rh D positive red cells except in an emergency. Alloantibody produced by transfusion of Rh D positive blood to Rh D negative women (or produced by exposure during sensitisation events in pregnancy such as ante partum haemorrhage /bleeding in pregnancy/miscarriage when an Rh D negative mother is carrying an Rh D positive baby) can cause Haemolytic Disease of the Fetus and Newborn (HDFN). HDFN occurs when either during a previous transfusion or a previous pregnancy as described above, alloantibody in mother’s blood crosses the placenta, binding to the fetal red cells. This breaks down the fetal red blood cells causing anaemia referred to as haemolytic anaemia.

The three most important red cell antibodies in clinical practice are RhD (anti D), Rhc (anti c) and Kell (anti Kell). 83% of our donors have the D antigen on their red blood cells and are D positive. The remaining 17% lack the D antigen and are D negative. (Source – NHS Blood and Transplant; Active Donor Base 2013/14). As well as D the Rh blood group system also has CE genes. CE produces four combinations; ce, Ce, cE or CE The most frequently occurring phenotypes of Rh CE and Rh D are Dce, cde, DCe, dCe, DcE, dcE, DCE and dCE. Sometimes we will communicate specifically with groups of donors who have specific phenotypes such as those who have the Dce or the ‘Ro’ subtype or phenotype. While Ro blood is rare amongst White European people, it is much more common amongst Black African and African Caribbean people. The Ro phenotype is over 10 times as common in individuals from Black backgrounds compared to individuals from White backgrounds and is very common in patients with sickle cell disease. Ro blood is needed for patients who have Ro blood group.

This allows a closer match for these patients and reduces the development of alloantibodies. Alloimmunnisation is exacerbated by differences in blood group distribution between patients with Sickle Cell Disease (SCD) and the predominantly white European blood donor population. A significant proportion of SCD and Thalasseamia patients have Ro phenotype cDe which is rare in donors of European origin. These groups of patients require on going blood transfusions. It is important that we group and type donors specifically (extended phenotype) for patients with this particular blood group as they require regular blood transfusions. Transfusion of red cells for these patients should be matched for ABO, D, C, E c, e and Kell. This fact that Ro donors are much more commonly found in the Black and Minority Ethnic (BAME) population is one of the reasons why we are asking many more BAME donors to donate blood. Ro blood is needed for patients who also have Ro blood. Often, these patients are those who require ongoing blood transfusions - many of our sickle cell patients. The Distribution of Blood Groups The chart below shows the distribution of blood groups amongst our donors.

It's important that we collect enough of the right type of blood in the right quantities to meet the needs of hospitals and patients across England. ABO Blood Group Blood Transfusion : Blood Groups and Compatibilities Contact us Blood Groups and Compatibilities There are many blood groups in the human population including ABO, Rh, Kidd, Kell, Duffy, MNS and Lewis. The most important of these are ABO and RhD. Transfusion with ABO incompatible blood can lead to severe and potentially fatal transfusion reactions. RhD is highly immunogenic and can lead to red cell haemolysis in certain settings. ABO antigens and antibodies The ABO blood group is the most important of all the blood group systems. There are four different ABO blood groups (see Table1), determined by whether or not an individual's red cells carry the A antigen, the B antigen, both A and B antigens or neither. Normal healthy individuals, from early in childhood, make red cell antibodies against A or B antigens that are not expressed on their own cells. These naturally occurring antibodies are mainly IgM immunoglobulins. They attack and rapidly destroy red cells carrying the corresponding antigen.

For example, anti-A attacks red cells of Group A or AB. Anti-B attacks red cells of Group B or AB. Name of Blood Group A and B antigens nil If ABO incompatible red cells are transfused, red cell haemolysis can occur. For example if group A red cells are infused into a recipient who is group O, the recipient's anti-A antibodies bind to the transfused cells. An ABO incompatible transfusion reaction may result in overwhelming haemostatic and complement activation, resulting in shock, renal failure & death (for more information please click here ). Rhesus D (RhD) antigen There are more than 40 different kinds of Rh antigens. The most significant Rh antigen is RhD. When RhD is present on the red cell surface, the red cells are called RhD positive. Approximately 80% of the Australian population are RhD positive. The remaining 20% of the population that lack the RhD antigen are called RhD negative. 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. Are they compatible? 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 RhD Positive RhD Negative Note that Group O RhD negative (O negative) red cells have neither ABO nor RhD antigens on their surface. O RhD negative red cells are issued in emergency situations where life saving transfusion is required prior to completion of a crossmatch.

Both RCH and RWH blood banks maintain a reserve of 5 emergency O RhD Negative red cells. (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. Avoiding ABO incompatible transfusions Most ABO incompatible transfusions occur as a result of improper patient identification at the time of collection of the pre-transfusion sample or administration of the blood product. The pre-transfusion check is carried out at the bedside by 2 members of clinical staff to ensure the right blood is transfused to the right patient. Positive patient identification prior to blood sample collection and labelling the specimen tube at the bedside is critical for accurate sample collection. Other blood cell antigen-antibody systems There are many other antigen systems expressed on red cells, white cells and platelets. Transfusion can cause antibodies to develop in the recipient. Some of these antibodies can cause transfusion reactions or damage the foetus.

The purpose of pretransfusion testing (or crossmatching) is to detect potentially harmful antibodies in a patient before transfusion and where possible select red cell units that will not react with them. Blood typing - ABO blood groups and Rh types Blood typing Blood typing What is blood typing? Blood typing is a test done to work out which blood type you have, or which blood group you belong to. Not everyone has the same blood group. There are several different blood groups, some of which are more common than others. People who have matching blood groups are said to be ‘compatible’. This means they could give or receive each other’s blood if necessary. Why is blood typing done? Blood typing is done whenever there is a need to know which blood group you have. For example: if you are pregnant – to make sure your blood and the blood of your baby are compatible if you need a blood transfusion or organ transplant – to make sure the blood you receive from a donor is compatible with your blood if you want to donate blood – so doctors know who they can safely give your blood to Blood typing is also sometimes done in newborn babies to test for certain diseases and conditions. How is blood classified?

Blood is classified into blood groups according to whether certain substances are present or not. These include antigens (types of sugars and proteins) found on the surface of your red blood cells and antibodies (types of protein) which are mainly found in plasma – the liquid component of your blood. All cells have different combinations of markers or “antigens” on their surface. Our immune system has learned to use these to help distinguish the body’s own cells (self) from foreign bodies (non-self), like bacteria or toxins. Your immune system learns to ignore your own normal antigens, but when it recognises that a foreign antigen has entered the body, it releases antibodies, which attach to the foreign entity and mark it so other parts of the immune system can remove and destroy it. In the case of blood cells, if your immune system recognises that foreign blood cells (i.e. blood cells that are not your type) have been introduced into your body (such as via a transfusion), it will mount an immune response using antibodies against the foreign cells. The most common systems used for classifying blood are the ABO blood group system and the Rhesus (Rh) type system.

The ABO blood group system Two of the antigens found on the surface of red blood cells are called antigen A and antigen B. The ABO group system for blood typing is based on which of these antigens you have on your red blood cells. You inherit the particular combination of blood group antigens you have from your parents. Blood type A: your red blood cells have antigen A only. Blood type B: your red blood cells have antigen B only. Blood type AB: your red blood cells have both A and B antigens. Blood type O: you have neither A nor B antigens on your red blood cells. In your plasma (the liquid component of your blood), you will have antibodies against whichever antigens you don’t have on your own red blood cells i.e. antigens that are foreign. These antibodies are present without you having contact with the “foreign” blood type. How this occurs is not clear yet. If you are blood group A, you will have antibodies to antigen B. If you are blood group B, you will have antibodies to antigen A. If you are blood type AB, you will not have antibodies to either A or B. If you are blood type O, you will have antibodies to both A and B.

The rhesus (Rh) system The other blood typing system commonly used is the Rhesus system, also called Rh system, named after the Rhesus monkey in which it was first discovered. In this system, if you have an antigen called the RhD antigen on the surface of your red blood cells, you are said to be Rhesus positive (Rh+). If you don’t, you are said to be Rhesus negative (Rh-). In Australia, about 83% of people are Rh positive. Combining your ABO blood group with whether you are Rh+ or Rh- means your blood can be classified as one of 8 possible types: O positive (O+) AB positive (AB+) AB negative (AB-) The most common blood group in the Australian population is O positive, with about 40 per cent of people having this blood type. On the other hand, only about 1 per cent of Australians are AB negative – the least common type.

One difference between the Rhesus system and the ABO group system is that Rh negative people don't usually possess antibodies against RhD (unless they have been previously exposed to it), whereas in the ABO group system if the antigen is absent from the red blood cell, the antibody against it is present in the plasma. Testing to see if you are Rh positive or Rh negative is routinely done during pregnancy, and for blood donors and for people receiving a blood transfusion. If a mother is Rh negative but her baby is Rh positive (which can happen if the father is Rh positive), the mother could produce antibodies that fight the baby’s red blood cells. This can happen if blood from the unborn baby enters the mother’s circulation. When there is a risk of this happening (threatened miscarriage, termination, chorionic villus sampling (CVS), abdominal trauma, at delivery), an injection called anti-D can be given to the mother to help prevent these antibodies against Rh positive blood being produced. According to the Australian Red Cross Blood Service 17% of Australian mothers will need injections of anti-D. Universal donors and recipients It is vital that any blood you receive from a donor is compatible with your own blood.

If it is not, you can get very sick or even die. If you need blood, ideally it will come from a donor who is the same ABO and Rh type as you. However, if it’s an emergency and an exact match isn’t available, other types of blood may be compatible – meaning that your immune system won’t react against them. The table below shows which blood types are compatible. Compatibility of ABO blood types ABO blood type of recipient ABO blood types recipient can receive A

Question: Under the ABO blood group system, what blood type can donate for blood transfusions safely to all other groups?
Answer: O