Immunohematology
The biological qualification of the donation in immuno-haematology determines the immuno-haematological characteristics (blood grouping, search for anti-erythrocyte antibodies and detection of anti-A and anti-B immune antibodies) of the donation, on the basis of the biological analyzes required by the regulations in force.
It thus aims to ensure the immuno-haematological compatibility of labile blood products vis-à-vis the recipient, and to inform the donor in the event of any particularity noted during his analyses. The donation is qualified on the basis of the results of the immuno-haematological analyses, after comparison with the results of previous donations, when they exist.
In addition, other complementary analyzes are carried out in order to provide specific blood products for certain patients: such as the phenotyping of systems other than the ABO, RH and KEL system. Patients with irregular antibodies should be transfused with Red Blood Cell Concentrates (RBCs) not presenting the corresponding antigen. In order to meet these demands, the Etablissement Français du Sang phenotypes certain blood donations in different systems depending on the stocks: Duffy (FY1 and FY2), Kidd (JK1 and JK2), MNS (MNS1 or M, MNS2 or N, MNS3 or S, MNS4 or s) and others according to specific needs .
ABO Blood Grouping
ABO blood grouping is carried out for each donation and uses the same techniques as grouping at the recipient, but has some particularities. In fact, in order to compensate for the absence of two blood samples, as for people who need to be transfused, blood grouping is carried out for a first donation twice, whereas for subsequent donations, it is carried out only once. , with verification of concordance with previous donations.
RH-KEL phenotyping
RH-KEL phenotyping consists of looking for antigens D, C, c, E, e for the RH system, and K for the Kell system. These antigens are tested because they are the most immunogenic (lead to immunization) in blood transfusions.
Antigen D
The D antigen is produced with antisera specific to blood donors who must detect the D variants likely to lead to allo-immunization of the D-negative recipient. Thus, the D VI variant must be labeled D positive in the blood donor, whereas for patients presenting this antigenic variability, they can become immunized against the D antigens. Thus, they must be considered D negative as receivers.
RH-KEL phenotyping
RH-KEL phenotyping is performed twice during the first donation. During the second donation, only one achievement is made with verification of the concordance with the first donation. Then, the RH-KEL phenotype is no longer realized.
Research of Erythrocyte Antibodies (RAE)
The search for erythrocyte antibodies (RAE) in blood donors is different from recipients in terms of screening. Indeed, in people likely to receive labile blood products, the search for irregular antibodies (RAI) is carried out on three complementary red blood cells. Whereas for donors, it is carried out on two pools of red blood cells.
When the screening is positive, the antibody identification technique is the same for the donor and the recipient. This antibody test is carried out on each donation in France, whereas in certain European countries, it is only carried out for the first donation.
Screening for immune anti-A and anti-B
The search for anti-A and anti-B immune antibodies is an immuno-haematological analysis carried out for each donation. This research is carried out using A1 and B, or A1B red blood cells. The presence of immune anti-A and/or anti-B antibodies must be mentioned on the label of labile blood products, with the exception of Red Blood Cell Concentrates (RCC) which only present residual plasma.