When Lyme disease is suspected, the most common initial test is a serological test, which measures the body’s antibody response to the Borrelia bacterium. This test is widely available and aids in diagnosis, but it does not always provide a definitive answer on its own, as antibodies may not yet have been produced in the early stages of infection, or they may remain in the blood for a long time after the infection has passed, even though the pathogen is no longer present.
If you have had a serological test, do not make the mistake of interpreting a positive/negative result as a diagnosis without further consultation.
If you have not yet received treatment, the serological (Western blot, immunoblot, ELISA, ViraMed, etc.) results are easier to interpret:
- If the IgM result is positive, it almost always indicates a real immune response, i.e. the body is defending itself against an existing acute infection. This is true even if the test itself warns of a possible false reaction. The reasons for this are caution and outdated references in the literature.
- If the IgG result is positive, it may be a sign of a past infection, but it may also be a sign of an acute process.
- Most importantly, if the result is negative, which is the case in more than half of acute infections, it does NOT rule out Lyme disease.
If we have previously received antibiotic treatment, the serological result cannot be interpreted unambiguously. A positive IgG result is highly desirable after successful treatment, while the IgM result cannot be interpreted unambiguously. Serology therefore does not provide information on the success or failure of treatment, but is indicative for a Lyme disease specialist.
If symptoms persist but the serological result is negative, or if we want to know for sure whether the bacteria are actually present in the body, it is worth performing a direct diagnostic test. This test looks for the bacteria directly in the blood and can therefore be more reliable in cases of early or difficult-to-detect infection (DualDur).
Both tests should be performed in consultation with a doctor, as the diagnosis of Lyme disease is always based on a combined assessment of symptoms, medical history and laboratory results. Choosing the right test helps to ensure fast and targeted treatment, which significantly improves the chances of recovery.
In the absence of symptoms, it is not worth performing laboratory tests. Therefore, the first step is always to record the symptoms and discuss them with doctors who are familiar with Lyme disease.
(C) Lyme Borreliosis Foundation
