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Diagnosing diseases caused by the presence of certain bacteria, viruses or parasites should be done in two stages. The second stage is the Western Blot test, which is a supplementary serological test that gives the final result of infection or no infection. Western Blot is used primarily in the diagnosis of Lyme disease.
Western Blot test – what is it?
The Western Blot test is a method for detecting specific proteins, used in molecular biology. The test is used to diagnose bacterial, viral and parasitic infections. The Western Blot test is performed with the patient’s blood serum. It is a qualitative method.
Western Blot test – diagnostics
The Western Blot test is used in the diagnosis of diseases caused by viruses as a method of detecting their cores. It is most often used in the diagnosis of hepatitis C, herpes, SARS, and after prior ELISA also HIV infection. The Western Blot test allows the diagnosis of parasitic diseases, including cysticercosis caused by the presence of armed tapeworm larvae, and some genetic diseases such as certain forms of Fanconi anemia.
However, one of the most popular applications of the Western Blot test is the diagnosis of bacterial diseases. These include tuberculosis and Lyme disease, in particular. The Western Blot test is also effective when H. pylori bacteria enter the body, which causes peptic ulcer disease. The test may also reveal neoplastic diseases.
Also read: “7 most dangerous viruses in the world”
Western Blot test – indications
Western Blot is used as the second step in disease diagnosis. The first is the ELISA test. The difference between these diagnostic test methods is in the characteristics of the results – the Western Blot shows a qualitative one, and the ELISA gives quantitative results, alerting that there are some antibodies in the patient’s blood. For this, it uses a certain scale. However, the Western Blot test shows which infection has occurred and at what stage the disease progresses. An indication for its use is a positive ELISA test result. Negative categorically eliminates the patient from further diagnosis.
Western Blot test – what does the test look like?
The Western Blot test looks for antibodies produced by the body against specific bacteria, viruses or parasites. These antibodies fight against antigens on the surface of microorganisms. Western Blot detects IgM and IgG antibodies. The first are produced by the body as a result of the first contact with the pathogen, and the rapid increase in their number indicates a recent disease process. In turn, IgG antibodies are produced much later, reaching their peak around 6 months after infection. They can stay in the body for several years.
To perform the Western Blot test, the test person’s blood serum is needed, as well as comminuted, killed culture bacteria. These, influenced by impulses of electric current, are broken down into fragments, including proteins, i.e. antigens. The next step in the Western Blot test is to transfer the antigens to a nitrocellulose membrane cut into strips and combine them with the patient’s blood serum. With the help of a special technique, the solution is stained, and the so-called stripes. Thus, the Western Blot test shows infection and the test is positive.
Western Blot test – when to do it?
Antibodies do not appear in the body immediately after infection. During this time, the so-called serological window where Western Blot testing is not reliable. In the case of Lyme disease, the serological window is 4 weeks. Only after this time can the ELISA test be performed, followed by the Western Blot test.
Long after this time, the Western Blot test result may be false-negative as the amount of antibodies fluctuates from time to time. Therefore, in the case of serious suspicions of the disease, it should be repeated every few weeks so as to find the right time for the appearance of antibodies. The reliable result of the Western Blot test may appear even in the fifth time.
Sometimes antibiotic therapy helps to achieve realistic results and confirm the infection by the Western Blot test. Taken by antibiotics, they modify the immune system, while increasing the number of produced antibodies. However, performing the Western Blot test during antibiotic therapy will not give the desired results yet. This may happen several weeks after your treatment has finished.
Western Blot test – interpretation of the results
There are several techniques for performing a test, and each laboratory uses different performance criteria. The Western Blot test should not be interpreted without referring to the symptoms of the disease being diagnosed. It is therefore important that the result is determined by a physician who specializes in treating the disease in question.
Simply interpreting the results of the Western Blot test is based on the observation of bands. The more there are, the greater the certainty of the diagnosis of the disease. Already 3 bands in the Western Blot test prove the presence of pathogens in the body, and 6 give absolute certainty.
In the case of Lyme disease, the IgM bands in the Western Blot test carry much more information. They are most active shortly after infection and also in chronic disease. They usually mean active Lyme disease. On the other hand, the detected IgG antibodies inform about a past infection or active, chronic Lyme disease.
- Western Blot positive indicates the presence of pathogens and indicates disease. It is worth noting, however, that the result also indicates IgG antibodies, and these may indicate a past infection. Thus, the Western Blot positive test is false positive.
- Western Blot negative by definition excludes disease. However, it is worth considering the possibility of a false result again. This may be due to the premature performance of the Western Blot test or the lack of antibodies due to a chronic disease that has been going on for some time, during which they have been eradicated by pathogens.
Test Western Blot – cena
Is Western Blot refundable? Unfortunately, unlike the ELISA test, this study is not financed by the National Health Fund. Therefore, in the event of a positive result indicated by the ELISA test, a supplementary test fee must be paid.
The cost of the Western Blot test is about PLN 200 for two classes, IgM and IgG. Sometimes, however, the price, depending on the center performing the test, may even reach PLN 300.
How to prepare for the test? Do you need to be fasting? Western Blot is a test that uses blood serum, therefore it is required to be collected for the tests. Therefore, it is worth visiting the health center feeling rested and well-rested, preferably in the morning. You do not necessarily need to be fasting.
Western Blot test – Lyme co-infections
Western Blot is not suitable for identifying Lyme co-infections. It gives a vague answer, exposing the patient to costs. In this case, it is better to use the reimbursable ELISA test, which will also be more precise.
We also recommend Shipping PCR test for Lyme disease and co-infections (tick test), which you can conveniently and safely buy at Medonet Market to send the tick to the laboratory.