Among EM cases, the combination of the C6 ELISA followed by the anti-Borrelia ELISA IgG plus VlsE/IgM or the inverse algorithm (anti-Borrelia ELISA IgG plus VlsE/IgM followed by the C6 ELISA) demonstrated the highest positivity rates of 100% (≤30 days) and 75.0% (>30 days), at a specificity of 92.7% (Table 6). The gene discussed is CD40LG; the disease is erythema multiforme.