what is blood test for lyme disease
Blood tests which look for antibodies to the bacteria that cause Lyme disease are the main test. This is known as serology. If antibodies have not developed sufficiently, it is possible for these tests to be negative despite active infection.
Lyme disease is diagnosed clinically based on symptoms, objective physical findings (such as EM, facial palsy, or arthritis), or a history of possible exposure to infected ticks, as well as serological blood tests. The EM rash is not always a bull's eye, i.e., it can be solid red.