Lyme disease is an infectious pathological condition caused by a bacterium, Borrelia burgdorferi, which is why it is also known as borreliosis. The disease is transmitted through a tick bite.
How Accurate Is The Elisa Test For Lyme?
Doctors base their diagnosis mainly in the medical history, clinical manifestations, and exposure to ticks, without depending on laboratory tests. There are several scientific articles arguing that the ELISA test has poor accuracy ranging between 33 and 49%, so a negative result does not mean that the patient does not have Lyme disease. Although ELISA test is a very effective test it can provide false positives or false negatives. In situations in which the ELISA test is decisive and radically changes the attitude of the doctor, it is usual to perform the ELISA test twice in a row or perform another test to ensure the result.
ELISA stands for the enzyme-linked immunosorbent assay. It is a laboratory technique that was designed by Swedish and Dutch scientists in 1971, which allows detecting small particles called antigens, which are usually fragments of proteins. The identification is specific, that means that it makes small segments of proteins stand out and cannot be confused with others.
In order to identify antigens, molecules with two coupled components are used: an antibody (which binds antigen specifically) and an enzyme (which activates and signals binding to the antigen). Before the discovery of the ELISA radioactive molecules were used instead of enzymes, which meant an unnecessary added risk in the laboratory and a higher cost.
Thanks to this technique, scientific studies have been carried out in fields such as biology, biochemistry, and medicine. In the hospital, it is mainly used to identify aggressor germs that are found in the blood, urine, sputum, etc. The technique soon became widespread with the use of simple and very cheap equipment that is still used today in many diagnostic centers around the world.
The results of the ELISA can take several days from when the sample is taken to study it. To pick them up you have to go to another appointment since the documentation alone cannot be interpreted by the patient. In the consultation, the doctor will be able to make the most appropriate interpretation of the result. If you are admitted, they will be informed during your stay in the hospital, or afterward if you have been discharged before. In case of an emergency consultation, you can get the results in less than an hour.
The ELISA is expressed in qualitative values that mean that either it is positive or it is negative. Only ELISPOT can provide quantitative results, but there are no standard limits for all studies. When the ELISA is positive it means that antigens have been detected in the collected sample, and therefore there are germs present. When it is negative, antigens have not been detected and the sample is not considered contaminated.
Lyme Disease Diagnosis
In the case of Lyme borreliosis, serological tests instead of clarifying the diagnostic problems can create doubts and when the doctor turns to the laboratory to confirm the clinical suspicion may be disappointed. The confirmation of clinical diagnosis by laboratory methods is, therefore, a delicate and difficult issue due to the occurrence of false positive results.
For the diagnosis of Lyme borreliosis, the history of exposure to tick bites in infested areas, along with clinical manifestations and positive serological results, may be sufficient. Even so, there is a broad international debate about the diagnostic utility of the different serological tests for the diagnosis of Lyme borreliosis. The options could be:
The direct examination in a dark field based on the morphology of Borrelias and its mobility with a rotation of the spirals against the hands of the clock can be an option in places with few resources.
The most common serological tests are: indirect immunofluorescence, haemagglutination, and ELISA and allow the detection of specific antibodies against B. burgdorferi between 3 and 6 weeks after infection (IgM antibodies after initial infection and IgG antibodies for years). The confirmatory method of serological tests is immunoblotting (Western Blotting) par excellence.