Last updated: May 21, 2019
Topic: HealthDisease
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The first measure in pre-transfusion testing is the designation of blood group ( ABO ) of the giver and the receiver. In add-on the presence of RhD antigen should besides be determined to guarantee that RhD negative receivers are non transfused with the RhD positive ruddy cells ( McCullough, 2005 ) . There is 99.5 % opportunity of acquiring blood compatibility if the receiver and the giver have the same ABO and RhD groups. However to do certain that the giver ‘s ruddy cells are 100 % compatible to those of the receiver ‘s, other antibodies that may be present in the receiver ‘s serum should besides be identified which is an of import portion of pre-transfusion testing ( Contreras, 1998 ) . The unknown antibodies present in the receiver ‘s serum can be detected by serological trials in which receiver ‘s serum is screened against the ruddy cells panel from different givers whose antigen look is known. The showing cells have the antigens that are able to trip the formation of clinically of import antibodies such as D, C, degree Celsius, E, vitamin E, K and Fya ( Contreras, 1998 ) . The chief purpose of the practical was to observe the presence of these clinically important antibodies in different receivers ‘ serum by indirect anti-globulin trial ( AGT ) , besides known as Coombs trial. In this trial, the IgG antibodies adhering to the ruddy cells can be observed indirectly by adding the anti-human globulin ( AHG ) reagent ( Overfield et al. , 2008 ) . If any agglutination is seen in the serum after the add-on of AHG so it shows that the antibody for the peculiar antigen is present. The major groups tested for in the experiment were Rh ( D, C, degree Celsius, E and vitamin E ) , Kell ( K ) and Duffy ( Fya ) . Indirect AGT is besides used to find the presence of weak D among the Rh- D negative persons ( Opoku-okrah et al. , 2008 ) .


The practical usher was provided and all the processs in the usher were followed throughout the experiment ( Refer to the practical usher ) . Serum samples from patients A, B, and C were examined against the ruddy cells panel ( 1 to 5 ) .


Table 1: Table exemplifying the agglutination activity of antibodies in patients ‘ serum samples against the givers ‘ ruddy cell antigens

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Red cells































* ( + ) indicates the positive consequence for agglutination and ( – ) indicates the negative consequence for agglutination.

The consequences for the staying serum samples against the ruddy cell antigens were acquired from the other group members. Table 1 demonstrates all the consequences obtained from all the group members. From the above tabular array, it can be seen that no agglutination activity was observed in the serum samples of patients A, C and D. This suggests that there were no antibodies present in the serum of patients A, C, and D against the antigens shown in the panel provided. In contrast antibodies in serum sample B showed agglutination activity against 1, 2, 3, 4, and 5 ruddy cells panel. Using the panel provided, it was found that serum from patient D contained anti-C, anti-D, and anti-E antibodies. Similarly, there was agglutination in serum sample of patient E against ruddy cells 1, 2, and 3 demoing the presence of anti-D antibody in the serum. In add-on, serum sample in patient F showed agglutination against 1, 2, and 4 ruddy cells. The serum in the receiver F was found to hold anti-C antibodies.


From the different form of agglutination reactions against different antigens, the antibodies present in the patient ‘s serum can be identified. The consequences showed the presence of clinically important antibodies in patients B, E and F. The presence of these antibodies against Rh system suggests that these patients are Rh negative as they are bring forthing isoantibody against the giver ‘s ruddy cells. It besides tells that the blood of patients B, E and F is non compatible to the giver ‘s. In contrast the serum sample of patients A, C and D did non demo any agglutination proposing that they are non bring forthing any antibodies against the giver ‘s ruddy cells antigens. Hence this suggests that blood of patients A, C and D is compatible to the giver ‘s blood.

Patients D and E do non hold any Rh D antigens on their ruddy cell surface and hence they are Rh D negative. Therefore it is really of import to guarantee that the patients E and F are transfused with Rh D negative ruddy cells. If they are transfused with Rh D positive ruddy cells so antibodies would be produced doing devastation of the ruddy cells ( Ravel, 1995 ) . Furthermore, if the patients E and F are pregnant adult females transporting Rh D positive fetus so there is a high hazard of acquiring Haemolytic Disease of Newborn ( HDN ) . This is because the female parent ‘s immune system identifies the fetus ‘s blood as “ foreign ” bring forthing IgM anti-D antibodies that can traverse the placenta and hence destructing babe ‘s ruddy cells ( Opoku-okrah et al. , 2008 ) .

The most common cause of terrible HDN is the presence of anti-D antibody ; nevertheless other clinically important antibodies such as anti-K and anti-c are besides responsible in doing different grades of hemolytic disease in the newborn. Anti-c causes milder disease compared to RhD HDN whereas presence of anti-K antibody is less important in doing HDN ( Contreras, 1998 ) . Other antibodies except anti-D, anti-K and anti-c antibodies are non likely to do foetal hemolytic disease even though the intervention may be required to the neonate. In peculiar pregnant adult females should be screened for antibody to find HDN and see the badness of the disease because anti-D being IgM can easy traverse the placenta ( Contreras, 1998 ) . Rh D negative female parents are given contraceptive anti-D Ig that destroys babe ‘s blood before female parent produces antibodies. Hence female parent can non bring forth antibodies responsible for doing HDN in her hereafter gestations ( Urbaniak and Greiss, 2000 ) .

The Rh grouping is the most immunogenic system and among all, RhD is the most important and usually detected easy ; nevertheless due to fluctuation in look there may be presence of weak antigens ( Kumar et al. , 2005 ) . Some persons have D antigen in their ruddy cells that react weakly or may non flush respond with anti-D reagents and hence may demo to hold Rh D negative. They are called weak D and can merely be detected by specific indirect AGT ( Contreras, 1998 ) . Weak D may originate because of weakening of D antigen, or RhD cistron encoding weak antigen or may besides be due to miss of a portion of the D antigen ( Kumar et al. , 2005 ) .

It is more of import to prove for the weak D antigen with givers because if the weak D ruddy cells are given to the Rh D negative receiver so the receiver ‘s serum produces anti- D antibodies ensuing in alloimmunisation to the Rh D antigen ( Kumar et al. , 2005 ) . This causes the devastation of ruddy cells from the giver and hence weak D givers are usually considered as Rh D positive ( Ravel, 1995 ) . In contrast if a weak D receiver is screened as Rh D negative and is given Rh D negative blood so there is no any injury to the receiver. Therefore indirect agglutination is non required to observe whether a receiver is weak D or non ( Klein and Anstee, 2005 ) .

The anti-globulin trial is the most utile trial that detects the clinically of import antibodies that is why the hazard of acquiring false negative consequences should be reduced. If the ruddy cells are non washed decently before adding anti-human globulin ( AHG ) so the serum globulin may still be present. This causes neutralization of the AHG which leads to false negative consequence. The hapless technique performed while reading the consequences may interrupt the agglutinates which may do to obtain false negative consequence ( Overfield et al. , 2008 ) . Rh typewriting is by and large done by agglutination, nevertheless sometimes this technique may non find the accurate typewriting for case in patients with autoimmune hemolytic anemia. Hence in such instances, manifold PCR can be performed to find the right Rh D type ( Cotorruelo et al. , 2000 ) .

It can be concluded that Rh blood grouping is really of import portion of pre- transfusion procedure after ABO blood grouping. Rh D, the most antigenic antigen, has a great function in transfusion mutual exclusiveness and gestation. In add-on indirect AGT plays a major function in pre-transfusion because it determines whether an person is weak D or non. It is really of import to test for weak D every bit good as for weak degree Celsius and weak Tocopherol.