NEFL and spinal cord disorder: When examining specific subgroups within the spinal cord disease group, the following serum NfL concentrations were observed: dogs with IVDH (n = 51) had levels of 99.3 pg/mL (IQR, 52.17–239.4), dogs with SM (n = 17) had levels of 50.70 pg/mL (IQR, 16.62–73.9), and dogs with other diseases, such as FCE and ANNPE (n = 8), had levels of 241.0 pg/mL (IQR, 90.9–976.3).