Serological tests: types of procedure, indications for conduction, contraindications

August 19, 2017 23:00 | Methods Of Diagnosis

Infectious diseases initiate the production of antibodies in the blood of a sick person.This is how the body's immune defense works.

Determination of the presence of antibodies to a particular virus or bacteria makes it possible to know about the onset of the disease before its main symptoms appear.Today, serological and bacteriological research gives the most complete picture.Therefore, we will talk in this article about the analysis for serological research.

What are serological studies of

Methods of studying biological materials of humans and animals that can detect antibodies or antigens that produce an organism in the form of a protective reaction in the fight against infections are called serological studies. Such methods are used to determine the causative agent of the infection, and with the aim of:

  • blood group determination,
  • study of immunity through the determination of its humoral level,
  • determination of tissue antigens.

To whom the serological examination of blood for parasites

, HIV, syphilis, antibodies, typhoid, on the markers of infectious diseases is prescribed, read below.

To whom it is assigned

Research is recommended for patients to establish a diagnosis for a wide range of infectious diseases.Serological tests are performed in determining the blood group, as well as to determine the effectiveness of treatment.

Why do it

The method is valued by specialists as a way to make a qualitative diagnosis of the disease.

  • If the patient is in the stage of the disease, then repeated studies are recommended to be carried out with an interval of about a week to observe the effectiveness of the treatment used.
  • Often serological tests are used to determine which pathogen caused the disease after the patient has suffered it.

Types of procedure

Methods of serological testing are based on various reactions:

  • The neutralization reaction relies on the property of antibodies of the immune serum to act as a neutralizing agent for toxins or microorganisms themselves, preventing their damaging effect.
  • agglutination reaction, which in its turn is subdivided into such subspecies:
    • direct reactions - they are used in the study of serum for the presence of antibodies.In the studied composition, the killed microbes are injected and, if a precipitate appears in the form of flakes, this means that the reaction is positive for this type of microbes;
    • , the indirect hemagglutination reaction is produced by introducing into the blood serum of red blood cells, on which antigens are adsorbed;These agents come into contact with the same kind of antigens present in the blood serum, as a result of which a scalloped precipitate falls out.
  • Complement reaction is used to detect infectious diseases.The method is realized through complement activation and observation of the reactions occurring in the medium under study.
  • The precipitation reaction of is accomplished by layering the antigen solution onto a liquid medium - the immune serum.Antigen for this method is used soluble.The reaction is that the antigen-antibody complex undergoes precipitation;The resulting precipitate is called precipitate.
  • The reaction using labeled antigens and antibodies to is based on the fact that microbes or tissue antigens treated in a particular way receive the ability to emit light under ultraviolet rays.The method is used not only for the diagnosis of antigens, but also for the determination of drugs, enzymes, hormones.

Contraindications for carrying out

Due to the fact that the method consists in studying the patient's biological material, it can not negatively affect a person.Therefore, there are no contraindications to use.

How the serological study is conducted, we will explain below.

Indications for the

method used to determine the infectious agent, including in such diseases:

  • cytomegalovirus infection,
  • HIV,
  • herpes,
  • toxoplasmosis,
  • inflamed parotid lymph nodes,
  • labirintopatiya,
  • infectious diseases, Sexually transmitted infections;
  • diphtheria,
  • Epstein-Barr virus,
  • shingles,
  • serum sickness,
  • presence of Staphylococcus aureus in the ears;
  • brucellosis,
  • infectious dermatitis,
  • bullous otitis,
  • blastomycosis,
  • staphylococcal infections,
  • hepatitis.

The method is also used to detect such diseases:

  • opisthorchiasis,
  • amoebiasis,
  • cysticercosis,
  • giardiasis,
  • pneumonia.

Preparation for procedure

No special preparation is required for the procedure. One condition should be observed: blood collection is done on an empty stomach.

The algorithm for the collection( collection) of blood( material) for a serological test is described below.

Conducting the analysis

Blood sampling is made from the ulnar vein.In order for the study to work out, the blood is not collected by a syringe, but by gravity.The needle is injected into the vein without a syringe and up to 5 ml of blood is collected into the tube.

During the procedure, the patient experiences a slight discomfort during the insertion of the needle into the vein.Follow-up does not cause any concern.

The transcript of the results of a serological blood test is described below.

Interpretation of results

The results obtained should be considered in conjunction with the clinical picture of the disease, testing the suspected diagnosis using several tests.This is due to the fact that the studies have a specific character and sometimes do not have absolute sensitivity to infectious diseases.

The price of a comprehensive serological blood test is described below.

Average cost of procedure

What price of the procedure will depend on the type of study.It consists of the cost of the product of analysis and the cost of antibodies to a particular causative agent of the disease. The average cost of the procedure is within 700 rubles.

Serological reactions are described in the video below: