Lyme disease is commonly diagnosed using IgG or IgM antibodies. These antibodies can be detected at higher levels in the later stages of illness, when more precise tests are unable to detect infection. IgM will increase in levels for approximately 4-6 week during early infection. Later, IgG will overtake IgM antibody and stay high for many months. Therefore testing for both classes of antibodies can help confirm diagnosis if performed at multiple time points during an individual’s illness course.