What is blood serum

The serum of blood is nothing more than its plasma, devoid of uniform elements and fibrin. It is formed as a result of certain chemical reactions. Serum can be obtained in two ways: by neutralizing fibrinogen with calcium ions and by natural clotting of blood.

The process of obtaining it is called "defibrination". Technologically, it looks like this: the blood collected in the vessel spontaneously folds, turning into a continuous clot of fibrin. The latter captures the uniform elements of the blood and, when standing for a long time, gradually squeezes out the liquid of yellow color. This is the blood serum.

The color of the serum is explained by the presence of a certain amount of bilirubin in it. Its increase indicates the presence of disorders of pigment metabolism. Normally, blood serum is transparent. But after eating slightly clouded, which contributes to the admixture of droplets of fat. The surface tension of blood serum is much lower than that of water.

Normally, the concentration of proteins in the serum varies between six and eight percent. In its composition, it contains mainly albumins (4.5-6.5%) and globulin (1.9-2.2%). The change in the proportions of these protein compounds, as well as their quantitative fluctuations, are of great clinical importance. However, this issue has not yet been fully explored.

Refraction of blood serum is virtually unchanged under the influence of physiological factors, such as the effect of hydrotherapeutic procedures or the usual intake of food. But prolonged fasting can lead to a decrease in the level of protein in the serum. On the contrary, muscular work practically does not affect its refraction.

The drop in the amount of protein in the blood serum is observed in acute infectious diseases. At the same time, the level of protein compounds independently comes to normal during the recovery period. An exception is tuberculosis, in which the total amount of protein, in particular globulin, is significantly increased.

With regard to the field of application, most often, blood serum is used in the biochemical blood test, its investigation for the presence of infectious diseases, to evaluate the effectiveness of vaccination, and to determine the group.

At present, two different methods are used in medical practice, one of which is the determination of the blood group by standard sera. To avoid errors, use exclusively active serums with a sufficiently high titer. Studies are conducted in a room where the air temperature should not exceed 25 degrees Celsius. The results should be evaluated no earlier than 5 minutes from the beginning of the study.

The technique of this procedure is as follows. Initially, it is necessary to determine the titer of diluted serum, which should not be lower than one to three. To this end, two large drops are taken from each test tube, which are applied to a flat surface. Then, in addition to each of these drops, other groups of red blood cells are added and mixed with serum. At the end of five minutes, the last drop is determined, where agglutination has passed. This is the greatest dilution. This process is called "hemagglutinating serum titer".

Next, a single large drop of standard serum is applied to the slide or dish with pipettes, after which a glass rod is connected with drops of blood. After five minutes, one drop of saline is added to each drop mixture, and then the results are evaluated. This is all about the process of determining the blood group by means of standard sera.

Drawing a line under all the above, it should be noted that today, blood serum is not only a necessary reagent, but also the main active substance of many drugs used to treat a large number of infectious diseases.