The species identification of blood

The definition of a species of blood - the question of its origin (animal or human). The species identification of blood is a prerequisite for further studies to determine blood group and its origin from a certain person. Such research can also check the version of the suspect about the origin of the blood on clothing and means of crime from a particular animal. Establishing the fact of origin of blood from a particular animal or poultry can also be an independent study with the poaching, AviaPromService and in other circumstances.

the reaction of Chistovika
Fig. 93. The Reaction Of Chistovicha.
Left - positive; on the right - negative.

Species blood is installed using the reaction of precipitation. In this reaction participate hood of spots (proteins of blood antigens) and precipitating serum (antibodies)that can only react with the proteins of humans or of a particular animal is horses, dogs, pigs, cattle and other Specific interaction of specific antigens and antibodies is manifested by precipitation (precipitate). Expert sets, which entered into reaction sera formed precipitate, and on this basis determines the species of blood stain. To control put also experiments with extracts from a subject outside the blood stains (Fig. 93).
The reaction of precipitation are very sensitive. Its result depends on the state of the blood proteins, mainly their solubility. Because improper handling of material evidence, in particular drying them at high temperature, can lead to blood proteins in insoluble condition that impedes the exercise of their type. Shipment wet clothes with blood leads to rotting and denaturation of proteins that also does not allow to determine the type of blood.

the reaction of precipitation in agar
Fig. 94. The reaction of precipitation in agar (explanation in the text).

The reaction of precipitation is usually in test tubes with a thin end. In them first place extract of the studied spots, and then a pipette on the bottom of the tubes down precipitating the serum. With a positive reaction on the border of contact serum and extracts a precipitate in the form of turbidity, having the form of a disk. The lack of sediment in a test tube with extraction of the subject-media permits in such cases to make a conclusion about a specific type of blood in the test spot. The negative reaction of precipitation with all precipitating sera can be associated with the destruction or insolubility of blood proteins, the lack of quantity or the presence of blood of any other animal. In this case we use the concentration of extracts and the use of more sensitive methods of species identification of blood - reaction precipitation on special paper for chromatography, reactions, precipitation, agar, methods of electroprecizia and other Reaction precipitation in agar apply also in cases when the turbidity hoods hinders research in the liquid environment. On the glass pour a layer of molten agar, after it cures it make grooves, one of which is placed the hood of the stain, and others precipitating the serum. They diffuse into the agar and when meeting hoods (antigens) and precipitating serum, if they are homologous, formed precipitate in the form of a strip of white color. If the hood and serum of meterologichna, precipitate is formed (Fig. 94).
To distinguish the blood of humans and animals (on the content of a number of inorganic elements) can also be used and the method of emission spectral analysis. Currently, with the aim of increasing sensitivity and resolution reaction precipitation as the Registrar of education pretipitata use laser light. The method allows to determine species of blood in mixed and sparingly soluble stains, traces of blood on contaminated objects-media.
Now for species identification of blood recommended method immunofluorescence, which agglutinating serum connected with fluorochrome. In case of positive result, when considering the object in ultraviolet rays seen the glow the color corresponding to the fluorochrome, which previously connected the serum.