The Western Blot test is performed when a patient is suspected of having Lyme disease. The Western Blot test looks for specific antibodies against the bacteria that cause Lyme disease. What is the Western Blot test? How to interpret the test results?

Western Blotis a test that looks for the antibodies your body makes against the bacteria that cause Lyme disease. There are antigens on the surface of the bacteria against which the body produces specific IgM and IgG antibodies. IgM.

Immunoglobulins M (IgM) - they are produced when our body first comes into contact with a given pathogen. The increase in the amount of IgM against a given pathogen indicates a recent disease process.

Immunoglobulin G (IgG) is produced by the body later than IgM, the highest level is reached about six months after infection and, unlike IgM antibodies, they can remain in the blood for a very long time, even several years.

Contents:

  1. Western Blot test - indications for the test
  2. Western Blot test - what is it?
  3. Western Blot test - when to perform?
  4. Western Blot test positive
  5. Western Blot test - negative

Western Blot test - indications for the test

Western Blot is used in the second stage of Lyme disease diagnosis - when the ELISA test (the first-choice test) gave a positive or doubtful result. However, it is not used when the ELISA test gave a clearly negative result.

Western Blot test - what is it?

The Western Blot test for Lyme disease accurately assesses antibodies to various bacterial fragments. The different antibodies to the individual bacterial fragments are finally graphically represented as black bands on the nitrocellulose membrane .¹

Do not perform this test shortly after the tick bite. Wait a minimum of 4 weeks. The price of the Western Blot test in both classes is about PLN 150-300.

  1. Two basic elements are needed to perform the test- the patient's blood serum and the killed and fragmented cultured Lyme disease bacteria.
  2. Under the influence of electric current, bacteria obtained from cell culture are decomposed into prime factors,incl. onbacterial proteins (antigens). Then these proteins are transferred to the nitrocellulose membrane. The film is cut into strips.
  3. The strip with antigens, after combining with the patient's blood serum, is stained using a special techniquei, detecting antibodies specifically related to Borrelia spirochetes antigens.
  4. In places where the patient's antibodies combine with proteins (antigens) of Lyme bacteria, we see characteristic stripes , called bands (which indicates Lyme infection. The test result is positive) .

Each band corresponds to a bacterial protein (antigen). If the Lyme proteins and the antibody don't combine, the band won't appear. Then the result is negative.

Important

Western Blot test - when to perform?

Early diagnosis of Lyme disease can be problematic due to the so-called serological window. This is the period from the onset of an infection until the body produces detectable antibodies. In the case of Lyme disease, the serological window lasts on average 4 weeks.

Performing tests within 4 weeks of a tick bite poses a risk of obtaining a false-negative result.

When carrying out a Lyme test, remember not to do it immediately after a tick bite, you should wait at least 4 weeks. This is roughly the time it takes for the immune system to produce the antibodies detected by this test.

Western Blot test positive

The presence of anti-Borrelia antibodies means you have Lyme disease. However, it is difficult to answer the question of whether the infection is active or not.

The IgG antibodies produced as a result of infection can be found in the blood even after 10, and sometimes even 20 years after the diagnosis of Lyme disease.

It also happens that the detected IgM antibodies (usually considered a marker of active infection) may be persistent and also do not indicate active infection.

Western Blot test - negative

The test may give a negative result in the initial stage of the disease, i.e. for the first few weeks after the bite.

The Western Blot test can be performed not only when Lyme disease is suspected, but also when infected with H. pylori bacteria (which causes peptic ulcer disease) or HIV.

The Western Blot test can give a false negative result also in another situation - when in old, chronic Lyme disease the production of antibodies has been stopped by the Lyme bacteria or when the antibodies have been completely used up in the fight against the disease.

If the suspicion of Lyme disease is strong,Western Blot testing is worthwhilerepeatseveral times, e.g. every few weeks, to find the moment when the antibodies are present in the blood.

The presence of antibodies in active Lyme disease changes and a person with a negative result has a chance of obtaining a positive result in a repeated test after a few weeks.Sometimes confirmation of illness is not obtained until the fourth or fifth time.¹

Some doctors try to confirm the infection in a different way: they treat the patient with antibiotics for a few weeks and after waiting 5-6 weeks they refer the patient to the Western Blot test.

Antibiotic treatment may not cure a chronic disease for such a short time, but it will modify the immune system enough that enough antibodies will build up in the blood to be detected. The Western Blot test result should be interpreted by a doctor who specializes in the treatment of Lyme disease .¹

The WB test can be performed during antibiotic therapy , but with antibiotics the chance of a positive result is slightly lower. The easiest way to detect the disease with this test is to perform the test 6 weeks after discontinuing antibiotic therapy.

Important

The test interpretation is the interpretation of the fringes. In general, it should be assumed that the more stripes, the more reliable the diagnosis. Three lines are a lot of certainty, and 5-6 lines are indisputable Lyme disease .¹

IgM bands are more diagnostic because they suggest active Lyme disease, ¹ although the detected IgM antibodies (IgM bands) may be persistent and do not indicate active infection. It turns out that IgM is high at the beginning of the infection and - as if contrary to logic - in chronic Lyme disease .¹

Increased level of IgG antibodies may be considered a remnant of a previous infection or it means a chronic, active disease.

Even a negative test result does not mean that Lyme disease does not occur. A negative test result only means that there are no antibodies to Lyme bacteria in the blood - this can be the case, for example, when the bacteria have entered the body and the production of antibodies has not yet started (doctors call this period the serological window).

Due to the varied technique of this research, it is difficult to find universal recommendations for interpretation. Each laboratory uses its own criteria.

The disease can only be diagnosed by a specialist on the basis of symptoms and laboratory tests. Western-Bblot cannot be interpreted without reference to symptoms.

It is therefore not recommended to monitor antibody titers to assess treatment efficacy.

Whattests should be performed to detect Lyme disease?

Source: x-news.pl/Dzień Dobry TVN

Bibliography:

1. Lyme disease and co-infections, ed. A. Klimaszewski, Lyme Disease Association

Category:

Research