The four sheep inoculated with classical scrapie had an average serum Nf-L concentration of 5.43 pg/mL throughout the asymptomatic portion of the incubation period which included 44 total data points (minimum, 2.09 pg/mL; maximum, 15.66 pg/mL; median, 4.99 pg/mL; 95% CI 4.65–6.21 pg/mL). The gene discussed is NFASC; the disease is scrapie.