2222. Borrelia burgdorferi, IgM antibodies (BlotAnalisis)

The Borrelia burgdorferi IgM antibody blot assay detects an immune response to specific Borrelia antigens. It is used to verify positive or equivocal (indeterminate) Borrelia burgdorferi IgM results, as it helps distinguish true infection from false positives, and is used to confirm early-stage Lyme disease (borreliosis).

Lyme disease is an infectious disease transmitted by the bite of a tick infected with Borrelia bacteria. The likelihood of transmission increases with the duration of the tick's attachment. The highest risk of infection occurs during the tick-active season – spring and summer. If the infection is not detected promptly, it can lead to serious complications, including damage to the joints (arthritis), heart (carditis), and nervous system (neuroborreliosis).

When Borrelia bacteria enter the body after a tick bite, the immune system begins producing protective antibodies. The first antibodies to appear are IgM antibodies, which signal the early stages of infection. If the initial IgM ELISA test is positive or indeterminate, it is always confirmed with a blot analysis. This is necessary to ensure the result is accurate and may indeed indicate Lyme disease.

Blot analysis detects IgM antibodies to specific proteins of B. burgdorferi, B. afzelii, B. garinii (OspC Ba, OspC Bb, OspC Bg, p39 and p41) and helps confirm the presence of infection.

When is testing necessary?

The test is recommended to confirm a positive or inconclusive screening test result – IgM antibodies to B. burgdorferi sl. If more than 30 days have passed since the tick bite, it is recommended to supplement the test with an IgG blot test for B. burgdorferi sl., as the IgM Western blot is less informative during this period.

Blot testing is not used to check the effectiveness of treatment.

Who needs testing?

• Adults and children experiencing flu-like symptoms (fever, chills, severe fatigue, headache, joint pain) without an obvious cause, especially if they live or have vacationed in areas where ticks are common.
• Those who have received a positive or questionable (indeterminate) result from a screening test for Borrelia antibodies and need a confirmed diagnosis.
• Those with skin lesions (acrodermatitis), joint pain (arthritis), neurological disorders, or heart problems (carditis).

What do the results mean?

A positive result indicates that the immune system has already encountered Borrelia, either recently or in the past, but does not determine whether the infection is currently active: IgM antibodies can remain in the blood for several months after treatment. Therefore, a definitive diagnosis is always made by a doctor, taking into account the symptoms, time of the bite, and the course of the disease.

A negative result means that specific IgM antibodies were not detected.

Laboratory diagnosis of Lyme disease should be a two-step process: first, a sensitive screening (ELISA), and only if the result is positive, specific confirmation by blot analysis. This approach meets international standards and ensures high accuracy in borreliosis diagnosis and justified treatment.

• Venous blood

In order to exclude factors that may affect the test results, we recommend to follow the preparation rules: