Borrelia burgdorferi p83-93 (IgM)

Borrelia burgdorferi p83-93 (IgM) – Tickborne Disease Panel (Vibrant America)

What is it?

The Borrelia burgdorferi p83-93 (IgM) marker tests for IgM antibodies against the p83-93 protein of Borrelia burgdorferi, the bacterium responsible for Lyme disease. IgM antibodies typically appear early in an infection and signal an active or recent immune response.

What does p83-93 mean?

The p83-93 protein is a high molecular weight antigen (83 to 93 kilodaltons) found on Borrelia burgdorferi. It is most often associated with late-stage Lyme disease, although detection of IgM against this protein can occasionally appear in early stages if the immune response is robust.

What does a positive IgM p83-93 result mean?

• May indicate an early or active immune response to Borrelia

• May suggest recent exposure to Lyme disease

• In some cases, IgM responses may persist beyond the acute phase, potentially reflecting ongoing immune activation

• Should be interpreted with caution, as IgM tests are more prone to false positives, especially in the absence of symptoms

Why is it important?

While p83-93 is more typically linked with chronic or late Lyme disease in the IgG phase, detection of IgM antibodies against this protein can occur early in infection or during reactivation. However, because IgM antibodies can remain elevated for weeks or months—and can cross-react with other infections—clinical correlation is essential.

Elevated p83-93 IgM levels may suggest:

• Early Lyme disease, particularly within 1–4 weeks of infection

• Recent Borrelia exposure with an ongoing immune response

• A possible false-positive in individuals with other infections or autoimmune conditions

Important context for interpretation:

• A positive IgM without symptoms or without other Borrelia markers may not indicate true infection

• Best interpreted alongside clinical history, symptoms (e.g., fever, rash, joint pain, neurological issues), and other Lyme-specific antibodies

• Confirmatory testing (e.g., immunoblot or PCR) is often recommended

Who should consider this test?

Individuals who:

• Have early signs of Lyme disease (e.g., erythema migrans rash, flu-like symptoms)

• Have been in tick-endemic areas within the past few weeks

• Are experiencing acute, unexplained symptoms after potential tick exposure

Clinical note:

The IgM response alone should not be used to diagnose Lyme disease without supportive symptoms or additional positive markers. Over-reliance on IgM testing can lead to misdiagnosis if not carefully interpreted.