Blood type （or blood group） is determined， in part， by the ABO blood group antigens present on red blood cells。A blood type （also called a blood group） is a classification of blood based on the presence or absence of inherited antigenic substances on the surface of red blood cells （RBCs）。 These antigens may be proteins， carbohydrates， glycoproteins， or glycolipids， depending on the blood group system。 Some of these antigens are also present on the surface of other types of cells of various tissues。 Several of these red blood cell surface antigens can stem from one allele （or very closely linked genes） and collectively form a blood group system。 Blood types are inherited and represent contributions from both parents。 A total of 30 human blood group systems are now recognized by the International Society of Blood Transfusion （ISBT）。
Many pregnant women carry a fetus with a different blood type from their own， and the mother can form antibodies against fetal RBCs。 Sometimes these maternal antibodies are IgG， a small immunoglobulin， which can cross the placenta and cause hemolysis of fetal RBCs， which in turn can lead to hemolytic disease of the newborn， an illness of low fetal blood counts that ranges from mild to severe。
Much of the routine work of a blood bank involves testing blood from both donors and recipients to ensure that every individual recipient is given blood that is compatible and is as safe as possible。 If a unit of incompatible blood is transfused between a donor and recipient， a severe acute hemolytic reaction with hemolysis （RBC destruction）， renal failure and shock is likely to occur， and death is a possibility。 Antibodies can be highly active and can attack RBCs and bind components of the complement system to cause massive hemolysis of the transfused blood。
Patients should ideally receive their own blood or type－specific blood products to minimize the chance of a transfusion reaction。 Risks can be further reduced by cross－matching blood， but this may be skipped when blood is required for an emergency。 Cross－matching involves mixing a sample of the recipient’s serum with a sample of the donor’s red blood cells and checking if the mixture agglutinates， or forms clumps。 If agglutination is not obvious by direct vision， blood bank technicians usually check for agglutination with a microscope。 If agglutination occurs， that particular donor’s blood cannot be transfused to that particular recipient。 In a blood bank it is vital that all blood specimens are correctly identified， so labeling has been standardized using a barcode system known as ISBT 128。
2血型的表达方式
Blood group BB型血
Blood group B has its highest frequency in Northern India and neighboring Central Asia， and its incidence diminishes both towards the west and the east， falling to single digit percentages in Spain。It is believed to have been entirely absent from Native American and Australian Aboriginal populations prior to the arrival of Europeans in those areas。
Blood group AA型血
Blood group A is associated with high frequencies in Europe， especially in Scandinavia and Central Europe， although its highest frequencies occur in some Australian Aborigine populations and the Blackfoot Indians of Montana。
Blood group OO型血
Blood group O （or blood group zero in some countries） individuals do not have either A or B antigens on the surface of their RBCs， but their blood serum contains IgM anti－A and anti－B antibodies against the A and B blood group antigens。 Therefore， a group O individual can receive blood only from a group O individual， but can donate blood to individuals of any ABO blood group （i。e。， A， B， O or AB）。
Blood group ABAB型血
Individuals have both A and B antigens on the surface of their RBCs， and their blood plasma does not contain any antibodies against either A or B antigen。 Therefore， an individual with type AB blood can receive blood from any group （with AB being preferable）， but can donate blood only to another type AB individual。
红细胞血型是1900年由奥地利的K.兰德施泰纳发现的。他把每个人的红细胞分别与别人的血清交叉混合后，发现有的血液之间发生凝集反应，有的则不发生。他认为凡是凝集者，红细胞上有一种抗原，血清中有一种抗体。如抗原与抗体有相对应的特异关系，便发生凝集反应。如红细胞上有A抗原，血清中有抗A抗体，便会发生凝集。如果红细胞缺乏某一种抗原或血清中缺乏与之对应的抗体，就不发生凝集。根据这个原理他发现了人的ABO血型。
Key words ＆ Sentences
关键词句全知道
In the year just ended， four of Japan’s top 10 best－sellers were about how blood type determines personality。
去年，日本国内十大畅销书中有四本都是关于血型如何决定性格的。
There is， there is A， type A， type B， type AB， and type O。
血型分为A型 、B型、AB型和O型。
The only difference is what sugar molecule is added to that point。
血型的唯一不同就是其中的抗原分子不同。
So for you to have O， both of your parents must be O。 An O can contribute an O。
如果你是O型血，你的父母都应该是O型血。也有可能其中一个是O型。
A person whose type blood is O may be safely transfused into persons with other blood types。
血型是O型能给所有其他血型的人输血的人。
It is absolutely necessary to type the patient’s blood before a blood transfusion。
输血前测定病人的血型是绝对必要的。
In a transfusion， donor and recipient should be of the same blood group to prevent agglutination。
输血时，供血者与受血者应是同一血型，以防止凝集。
In the mid－1950s it was found that fetal cells in the amniotic fluid could be used to determine fetal sex and blood type。
在50年代，人们发现羊水中的胎儿细胞能用来确定性别和血型。
Handset radiation caused disease made difference to blood type of patient。
手机辐射致病因人血型而异。
The ABO antigens make certain Blood types incompatible for transfusion。
ABO抗原使某些血型在输血时不能兼容。
There are three main blood types： A， B and O。
一共有三种主要的血型：A型、B型及O型。
Blood typing： Classification of Blood by inherited antigens associated with erythrocytes （red Blood cells）。
血型分类： 根据由遗传决定的红血球中的抗原来将血液分类。
The DNA method will be far superior to the dental records and blood typing strategies currently in use。
DNA方法将远比牙印记录和当前正被使用的血型鉴定方法要优越得多。
Banked blood lasts only 42 days， has to be refrigerated and must be cross－matched to patients to avoid negative reactions with incompatible blood types。
血库中的血液必须用冰箱保存并只能存放42天，为避免不同血型间的不相容所产生的不良反应，还必须与病人的血液做交叉配血试验。
Each of us has one of these basic blood types。
我们每个人都属于这几种基本血型中的一种。
In fact， nearly 100％ of Native Americans have type O blood， while 80 to 90％ of the global population has type O and type A blood。
事实上，美国的印地安人将近100％都是O型，而全世界光是Ｏ型跟Ａ型的人就占了地球人口80％～90％之多。