Serology is a section of immunology that studies the reactions of antigens to serum antibodies.
Serological studies are a techniquestudy of certain antibodies or antigens in the serum of patients. They are based on responses of immunity. Widely apply these studies in the diagnosis of various infectious diseases and when determining the blood type of a person.
Serological analysis is prescribed for patients withsuspected of any infectious disease. This analysis in conflicting situations with the diagnosis will help to establish the causative agent of the disease. Also, further treatment depends on the results of serological studies, since the determination of a particular microorganism contributes to the appointment of a specific treatment.
Serological studies involve taking biological material from a patient in the form of:
- blood serum;
- saliva;
- fecal masses.
The material should be in the laboratory as soon as possible. Otherwise, it can be stored in the refrigerator at a temperature of +4 or by adding a preservative.
To the collection of these analyzes specificallyprepare the patient is not necessary. Research is safe. Blood sampling is performed in the morning on an empty stomach, both from the ulnar vein, and from the ring finger. After sampling, the blood should be placed in a sterile, sealed tube.
Human blood performs in the bodya lot of functions and has a very wide field of activity, and therefore there are many options for blood research. One of them are serological tests of blood. This is a basic analysis conducted to identify certain microbes, viruses and infections, as well as the stage of development of the infectious process. Serologic blood tests are used for:
- determination of the number of antibodies against viruses andmicrobes that are in the body. To do this, the antigen of the pathogen is added to the blood serum, after which the ongoing chemical reaction is evaluated;
- antigen determination by introducing antibodies into the blood;
- determination of the blood group.
Serological blood tests are alwaysappointed twice - to determine the dynamics of the disease. A single determination of the interaction of antigens and antibodies indicates only the fact of infection. To reflect the full picture, where you can observe an increase in the number of links between immunoglobulins and antigens, a repeated study is necessary.
Increasing the number of antigen-antibody complexesin the body indicates the presence of infection in the patient's body. Conducting specific chemical reactions with the growth of these indicators in the blood contribute to the definition of the disease and its stage.
If the result of the analysis shows the absenceantibodies to pathogens, it indicates the absence of infection of the body. However, this rarely happens, as the appointment of a serological analysis already indicates the detection of symptoms of a particular infection.
You should carefully monitor the conditions inwhich is done blood sampling. Do not allow anything to enter the bloodstream. The day before the analysis should not overload the body with fatty foods, spirits and sugary drinks. It is necessary to eliminate stressful situations and reduce physical exertion. Biological material should be taken to the laboratory as soon as possible, as long-term storage of serum leads to partial inactivity of antibodies.
In laboratory practice, serological blood testing is complementary to bacteriological examination. The main methods are presented:
one.The reaction of fluorescence, which is carried out in two stages. First, antibodies are detected in the circulating antigen complex. Then antiserum is applied to the control sample, followed by incubation of the preparations. RIF is used for the rapid detection of the causative agent of the disease in the test material. Reaction results are evaluated using a fluorescent microscope. Evaluated the nature of the glow, shape, size of objects.
2. Agglutination reaction, which is a simple gluing of discrete antigens with antibodies. Allocate:
- direct reactions used for detectionantibodies in the serum of the patient. A certain number of killed microbes is added to the serum and causes the formation of a precipitate in the form of flakes. Serological tests for typhoid fever involve the direct agglutination test;
- passive hemagglutonation reactions basedon the ability of red blood cells to adsorb antigen on its surface and cause adhesion upon contact with the antibody, and loss of visible sediment. It is used in the process of diagnosing infectious diseases to identify hypersensitivity to certain drugs. When evaluating the results, the appearance of the precipitate is taken into account. A precipitate in the form of a ring at the bottom of the tube indicates a negative reaction. Lacy sediment with jagged edges indicates the presence of a particular infection.
3An enzyme immunoassay based on the principle of attaching an enzyme label to antibodies. This allows you to see the result of the reaction by the appearance of enzyme activity or by a change in its level. This research method has several advantages:
- very sensitive;
- reagents used are universal, and they are stable for six months;
- the process of recording the results of the analysis is automated.
The above serological methodsStudies have some advantages over the bacteriological method. These methods allow you to determine the antigens of pathogens in a few minutes or hours. Moreover, these studies can detect pathogen antigens even after treatment and the death of the bacteria that cause it.
The results of serological studies arevaluable diagnostic method, but have auxiliary significance. The basis for the diagnosis is still clinical data. Serological tests are done to confirm the diagnosis, if the reactions do not contradict the clinical picture. Weakly positive reactions of serological studies without confirming its clinical picture can not be the basis for diagnosis. Such results should be taken into account when a patient in the past had a similar disease, and he underwent a course of appropriate treatment.
Determination of hereditary signs of blood,confirmation or denial of paternity, the study of hereditary and autoimmune diseases, setting the nature and source of infection in epidemics - all this helps to identify serological blood tests. Decoding the results provides information on the presence of specific proteins for infections such as syphilis, hepatitis, HIV, toxoplasmosis, rubella, measles, and typhoid fever.
