IgM antibody test: tests for the IgM antibody present in the blood when you have an infection.
 IgG antibody test: tests for the IgG antibody that fights bacterial infection.
The IgM and IgG tests are performed first. If you test positive for these antibodies, it’s likely that you have or had Lyme disease. A positive result on the ELISA test means Lyme disease is likely, but must be confirmed with a Western blot. The Western blot test is the definitive diagnosis for Lyme disease.