What indicates a positive diagnosis for Lyme disease?

A positive diagnosis for Lyme disease is indicated by the detection of Borrelia burgdorferi, the spirochete bacterium responsible for the disease. This detection can be confirmed through laboratory testing, including polymerase chain reaction (PCR) tests, which directly identify the bacterial DNA, or through serological tests that check for antibodies against the bacterium. In the context of Lyme disease, identifying the presence of B. burgdorferi is crucial since the initial symptoms may be nonspecific, and testing confirms the diagnosis.

The other options do not accurately indicate a diagnosis of Lyme disease. For instance, a scaly rash may suggest a different skin condition rather than pointing specifically to Lyme disease. A high white blood cell count can occur in various infections or inflammatory conditions but is not specific for Lyme disease. Lastly, a negative ELISA test would generally indicate that the person does not have Lyme disease since the ELISA test is part of the standard two-tier testing approach for confirming Lyme disease, with a negative result suggesting the absence of active infection. Therefore, the presence of B. burgdorferi is the definitive marker for accurately diagnosing Lyme disease.