is a great place to look up some of these crazy tests they run on us.
From what it says: "Two tests are typically used to detect and confirm Lyme disease. The Centers for Disease Control and Prevention (CDC) recommend that an ELISA or IFA test method be used first to measure B. burgdorferi IgM and/or IgG antibodies." -- my guess is the dermo tested you for Lyme Disease. And it showed up negative.
I don't know much about
Lyme Disease, so I don't know if the blood test is definitive or if it might be one of several things used to diagnose Lyme.