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The definition of the blood group

The definition of the blood group carried out to identify the possibilities of its origin from a certain person. In erythrocyte, and serum enzyme systems of blood contains a large number of inherited antigens (proteins), some combination of which every system is characterized by one or another group of blood. Group membership is defined as the traces of blood on the material evidences and sent blood samples taken from victims and suspects. Antigenic mapping of a set of blood in various systems in the study tracks and samples allows to speak about the possibility or impossibility of origin of traces of blood on the material evidence from the person. It is necessary to consider that in the liquid blood can define groups of different systems of blood is much wider, than in dried blood spot, due to the decreased activity in many group antigens of blood during its drying, destruction of the group properties under the influence of various environmental factors. The expert group identify or distinguish traces of blood can be in some cases limited to a small size of the studied blood stains.
First of all examine group antigens in blood samples of victims, accused persons or suspects, then - group antigens in the blood traces on material evidence. After the analysis of blood samples and blood on the material evidences expert determines whether blood of a person with blood on material evidence. If there is no match, the expert is entitled to draw the conclusion that the blood on material evidence cannot belong to the individual. At coincidence of antigenic characteristics of a sample of blood and blood on the material evidences it cannot be stated that the blood on the real proof was precisely from that person, because there may be and others, with the same group characteristic of blood. The more will be explored signs, the more accurate will be the expert's response.
RBC group. The traces of blood in the identification of groups of erythrocyte systems AVO, MNSs, R, Lewis, RH.
The system AB0 a high polymorphism and extremely high stability of its antigens to external influence is of paramount importance for the differentiation of blood traces. The system AB0 all people are divided into four main groups: 0αβ (I), Аβ (II), Вα (III) and AVO (IV). In persons of group I in erythrocytes contain weak antigen 0, and in the serum antibodies α and beta; in persons of II group - antigen and antibody β; in persons of group III - antigen and antibody alpha, in persons of group IV - a and b antigens (serum antibodies α and beta is not available). The average frequency of occurrence of the four groups system AB0 respectively - 35, 35 and 20 and 10 %.
As established in the blood of most people with groups And (II), (III) and AVO (IV) contains the accompanying H antigen, close by their nature to the antigen 0. Therefore, the system AB0 now called system AB0 (N). The definition of H antigen has significantly expanded opportunities for the group differentiation of blood. In turn, the study of antigen And allowed to divide it on a "strong") and A2 ("weak"), which significantly expands the group differentiation of blood. Method of differentiation subgroups of system ABO using a special herbal Pitigliano (lectins) first developed in our country.
Crucial for establishing blood group system AB0 in the studied spot has detecting whether any of the antigens, since antibodies α and beta in the blood of different persons have different power intensity, more vulnerable to external shocks, owing to what can be stored in the spot, with only a slight time, just a few days. Antigens as a, b, 0 and N under appropriate conditions may persist in the blood stain dozens, hundreds and even thousands of years.