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Blood Group

الكلية كلية طب الاسنان     القسم  العلوم الاساسية     المرحلة 2
أستاذ المادة وسن نجم عبد السادة الربيعي       23/02/2019 00:10:27

the determination of the abo and rh (d) blood groups

four blood types involving the a and b antigens have been recognized: a, b, ab and o .these letters indicate the type of antigen present on the red cells. if only the a antigen is present on the red cells, the person has type a blood if only the b antigen is present, the person has type b blood. type ab red cells have both antigens, and type o have neither. of course no one has antibodies to his or her own blood type antigens, or their plasma would destroy own cells.

table (1) :the abo blood group system.


blood type
antigens
(agglutinogens)
in rbcs antibodies
(agglutinins)
present in serum
can take from
can donate to

percentage

a a anti-b a, o a, ab 42%
b b anti-a b, o b, ab 9%
ab a ,b none ab, a, b, o ab 3%
o none anti-a, anti-b o o, a, b, ab 46%

anti-a serum and anti-b serum when combined with a blood sample in the laboratory, each antiserum causes the corresponding red cells to clump together in a process known as agglutination .the blood’s pattern of agglutination, when mixed separately with these two sera, reveals its blood type (fig.1). type a reacts with anti-a serum only type b reacts with anti-b serum only .type ab agglutinates with both, and type o agglutinates with neither a nor b .

figure (1): blood typing .
the rh factor
more than 85% of the population has another red cell antigen group called the rh factor, named for rhesus monkeys, in which it was first found. rh is also known as the d antigen. people with this antigen are said to be rh positive those who lack this protein are said to be rh negative (15%),but their plasma normally does not contain the antibody .in iraq the rh factor is present on the red cells of about 92% of the people and absent from those of remaining 8%.
rh incompatibility is potential problem in certain pregnancies. a mother who is rh negative may develop antibodies to the rh factor of an rh-positive fetus (the fetus having inherited this factor from the father). red cells from the fetus that enter the mother’s circulation during pregnancy and childbirth evoke the response. in a subsequent pregnancy with an rh-positive fetus, some of the anti-rh antibodies may pass from the mother’s blood into the blood of her fetus and destroy the fetus red cells. this condition is called hemolytic disease of the newborn (erythroblastosis fetalis).

the principle
a droping of blood is mixed with anti-a, anti-b and anti-d sera and examined for agglutination .

purpose
to determine the group abo and rh factor .

apparatus and reagents
slide method :
1.anti-abo sera kit (available commercially).
2.glass slides .
3.microscope .
4.sticks for mixing .
5.lancet .
6.blood sample .




procedure
1.divide a microscope slide into three areas a, b and d .
2.prick a finger with a sterile lancet, and place one droping of blood in areas a, b and d divisions.
3.add one droping of anti-a, anti-b and anti-d into each division (a, b and d) respectively.
4.mix them (blood and serum) separately and well with a glass rod or a clean match stick .
5.after two minutes observe the area for the evidence of agglutination of the red cells (read microscopically ).
6.find out the blood groups using the following table :

table (2)
blood group & rh type reaction with
anti-d serum anti-b serum anti-a serum
a+ + – +
a? – – +
b+ + + –
b? – + –
ab+ + + +
ab? – + +
o+ + – –
o? – – –

(+) indicates agglutination .
(–) means no agglutination .


المادة المعروضة اعلاه هي مدخل الى المحاضرة المرفوعة بواسطة استاذ(ة) المادة . وقد تبدو لك غير متكاملة . حيث يضع استاذ المادة في بعض الاحيان فقط الجزء الاول من المحاضرة من اجل الاطلاع على ما ستقوم بتحميله لاحقا . في نظام التعليم الالكتروني نوفر هذه الخدمة لكي نبقيك على اطلاع حول محتوى الملف الذي ستقوم بتحميله .