If you develop early symptoms consistent with Lyme disease such as the erythema migrans rash and you know you were recently bitten by a tick, or even if you just spent time in tick-infested areas, you should see your doctor to determine if you have Lyme disease. Keep in mind that you may have been bitten by a tick without even knowing it. Generally, the presence of the erythema migrans rash along other common symptoms and a personal history that suggests tick exposure is enough for a doctor to diagnose Lyme disease.

If no rash is present, the doctor may want to perform laboratory tests to determine if you have antibodies in your blood that are directed against the Borrelia burgdorferi bacterium. Positive results on these tests can help confirm a diagnosis, but the tests are not perfect. There is a chance of false positive results and negative results do not necessarily mean that you do not have Lyme disease. Tests include the enzyme-linked immunosorbent assay (ELISA) and the Western blot test for B. burgdorferi antibodies, and the polymerase chain reaction (PCR) test to detect B. burgdorferi DNA.