BTG3 and Erythema nodosum: Due to clinical suspicion of erythema nodosum, laboratory tests were assigned which resulted in: ANA antibodies 1:100, ANA panel – normal; serology for Borrelia Burgdorferi – IgM – 2.05 (a positive result; referent values above 1.1 is considered positive), IgG – 0.56 (a negative result; referent values under 0.9 is considered negative).