Lyme Disease Blood Test Results Explained: What They Mean
Also known as: lyme disease test, lyme blood test results, lymes blood test results, ELISA Western blot
Lyme disease blood test results come from a two-step antibody process: a screening ELISA (or EIA), then a confirming Western blot if the first step is positive or borderline. Results show whether your immune system has made antibodies to the bacteria that cause Lyme — not whether the bacteria are still present. Because antibodies take a few weeks to develop, testing too early after a tick bite can produce a false negative.
How blood tests are used
The CDC recommends a two-tiered testing approach for Lyme disease. Blood tests detect your immune response to the bacteria, not the bacteria itself, so timing matters — antibodies may not be detectable in the first 1–2 weeks of infection. Results are always interpreted alongside symptoms and possible tick exposure.
Key Lyme disease tests
| Test | What it checks |
|---|---|
| ELISA (or EIA) | First-step screening test that detects Lyme antibodies. Sensitive but can give false positives. |
| Western blot | Confirmatory second step run when the ELISA is positive or equivocal; checks for specific antibody bands. |
| IgM vs IgG bands | IgM suggests recent infection; IgG suggests longer-standing infection. |
What Lyme results mean
- A positive ELISA followed by a positive Western blot supports a Lyme diagnosis in the right clinical context.
- A negative ELISA early in infection may be a false negative — retesting in 2–4 weeks may be advised.
- A positive ELISA with a negative Western blot is generally considered negative for Lyme.
- Antibodies can persist for months to years after treatment, so tests aren't used to judge cure.
Understand your own results
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Frequently asked questions
What do Lyme blood test results mean?
Lyme ("Lymes") blood test results report antibody findings from the two-tier process. A positive ELISA plus a positive Western blot supports Lyme in the right clinical context. A negative ELISA early after a bite may be a false negative. A positive ELISA with a negative Western blot is generally treated as negative. Your clinician interprets bands, timing, and symptoms together — the lab slip alone does not diagnose or rule out Lyme.
How soon after a tick bite can Lyme be detected in blood?
Antibody-based Lyme tests usually can't detect infection in the first 1–2 weeks, because your body hasn't produced enough antibodies yet. Testing is most reliable a few weeks after exposure. Early Lyme with the classic bull's-eye rash is often treated based on symptoms without waiting for blood tests.
Why do I need two Lyme tests?
The two-tiered approach improves accuracy. The first ELISA test is sensitive but can produce false positives, so a positive or borderline result is confirmed with a more specific Western blot. Both must be positive (in the right clinical setting) to support a diagnosis.
Can Lyme blood tests stay positive after treatment?
Yes. Antibodies can remain detectable for months or even years after successful treatment, so a positive test doesn't necessarily mean active infection. That's why Lyme tests aren't used to confirm that treatment worked.
Related biomarkers
See also
Sources
This page draws on the following authoritative references.
- Clinical Testing and Diagnosis for Lyme Disease — CDC
- Laboratory Diagnosis of Lyme Borreliosis — Clinical Microbiology Reviews
Medically reviewed by Antonieta Rueda, MD and Kyle R. Toth, MD · Last reviewed July 22, 2026
This article is for informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Blood tests are interpreted by a clinician alongside your symptoms and history. Always consult your healthcare provider about your results.