Borrelia (Borrelia burgdorferi), antibodies. Western blot, quantitative (recomBead)

Why this test?

To determine whether a person has been infected with Borrelia burgdorferi bacteria. This allows you to confirm the diagnosis of tick-borne borreliosis.

To monitor the effectiveness of treatment.

When is it prescribed?

The test is prescribed for symptoms of tick-borne borreliosis. In the early stages, the following can be observed: migrating erythema, elevated temperature, chills, headache, rapid fatigue, nausea.

Additional evidence for the analysis is a tick bite (a few days or weeks before the first symptoms appear). In some cases, it is even possible to test the tick itself for B. burgdorferi. If the result is positive (that is, the tick is a carrier of borreliosis), then the bitten person should take the test himself (it will be possible to detect antibodies after a few weeks).

Symptoms of borreliosis in the later stages: periodic pain in the joints, bones and muscles, meningitis, paralysis of the facial nerve, numbness of the limbs, memory disorders. In addition, the analysis is prescribed if necessary to ensure the success of the treatment.

Test information

This test detects antibodies to Borrelia burgdorferi, which are produced by the human body in response to infection. That is, their presence means that a person was infected with these bacteria.

B. burgdorferi belongs to the group of spirochetes and causes tick-borne borreliosis (Lyme disease) in humans.

A person becomes infected if they are bitten by a tick that has itself been infected with B. burgdorferi. Ixodes ticks, carriers of borreliosis, are the most common group of ticks, they are found everywhere in the temperate zone of the Northern Hemisphere. Most often, people are infected during the period of activity of ticks - in spring and summer.

The incubation period of borreliosis is several weeks. In the early stages, the following symptoms may be observed: fatigue, chills, headache. Also, with borreliosis, a characteristic rash sometimes occurs - erythema migrans (ring-shaped reddening of the skin, which gradually expands). If the disease is not treated, serious problems can arise: joint pain, meningitis, numbness of the limbs, paralysis of the facial nerve, memory disorders and (in some cases) damage to the eyes and heart. Treatment of the disease, as a rule, is effective.

Upon infection, human lymphocytes begin to produce antibodies - special proteins (immunoglobulins) that must neutralize the bacteria. Immunoglobulins M (IgM) appear in the blood first, a few days after infection. However, it is usually possible to detect them later (after 2-3 weeks). After about 6 weeks, the concentration of antibodies reaches a maximum and then gradually decreases. Antibodies of another type - immunoglobulin G (IgG) - usually appear a little later and are present in the blood longer.

The number of antibodies is expressed as a titer. Antibody titer is the maximum dilution of the solution at which antibodies are still detected in it. For example, a titer of 1:16 means that if the blood serum is diluted 16 times, antibodies can still be detected in it (and if it is diluted more, then the antibodies are no longer detected).

The titer is called high (for example, 1: 612) or low (for example, 1: 4).

A high titer is more reliable. At the same time, it is important to remember that this is not the same as the severity of the disease. After all, it is not about the number of bacteria, but about the number of antibodies against them.

The antibody test is recommended to be performed in two stages. The first step is to determine the titer of IgM and IgG antibodies. If the result is positive or ambiguous, then you need to pass another analysis - western blot (immunoblot).

Western blot is performed only in case of confirmed (IgG+, IgM+) or doubtful ELISA result. It is impractical to carry out a western blot without a preliminary stage of diagnosis by the ELISA method or with a negative ELISA result.

Western blot is an immunoassay that detects specific proteins in tissues or blood. When it is carried out, a special gel is used, on one end of which a sample with protein is applied. Under the influence of electric current, proteins move, are divided by shape and size and form separate strips. They are then washed onto the membrane in contact with the gel. Labeled antibodies are used to identify membrane-bound proteins. A sample of the patient's blood or tissue is mixed into the blot, antibodies are bound and detected as labeled antibodies to human immunoglobulins.