What is this test?
This serology test measures IgM antibodies to Borrelia burgdorferi. It is interpreted within a validated two-step algorithm, not as stand-alone proof of Lyme disease. Immunoblot is normally the second step after a reactive or equivocal initial test.
Why might it be ordered?
- For compatible symptoms and a realistic possibility of tick exposure, when clinically indicated.
- As the second step after a positive or equivocal initial serology test.
- Not to check whether treatment has cleared antibodies, because they may remain for a long time.
What sample is needed?
A blood specimen is used. Report when symptoms began and possible exposure occurred, because timing determines which antibody classes and steps are appropriate.
How should you prepare?
Special dietary preparation is usually unnecessary. Report antibiotics and previous Lyme results without changing treatment on your own.
How should you understand the result?
The result reports IgM in the immunoblot pattern. IgM should be considered only when symptoms have lasted no more than 30 days; later isolated IgM has a high risk of misleading reactivity.
Sources and editorial status
This patient-facing text is an editorial draft. It should be approved by a laboratory physician before official publication.