Final answer:
The initial diagnostic test for Lyme disease is the enzyme immunoassay (EIA), which detects antibodies against the bacteria. If the result is positive, a confirmatory Western blot test is performed. These tests, combined with symptoms and potential exposure history, are used to diagnose Lyme disease.
Step-by-step explanation:
The first diagnostic test typically used to determine if a patient has Lyme disease is the enzyme immunoassay (EIA). This test is designed to detect antibodies against the bacteria that cause Lyme disease. If the initial EIA test result is indeterminate or positive, the Centers for Disease Control and Prevention (CDC) recommends that a second test, the immunoblot or Western blot test, be conducted to confirm the diagnosis.
The EIA test can sometimes yield a false positive due to the presence of other diseases, which is why the follow-up Western blot test is important. It provides more specific information, helping to distinguish between Lyme disease and other conditions. If both tests are positive in conjunction with the presence of symptoms like a bull's-eye rash, (which is characteristic of Lyme disease but not always present), and potential exposure in areas where Lyme disease is common, a diagnosis can be confidently made. The primary treatment for Lyme disease is antibiotics, and early intervention is crucial for a successful outcome.