One study further detailed the differences in threshold values (assessed by Simoa) according to parkinsonian syndromes (Quadalti et al., 2021): for example, to differentiate PD from MSA, the best cut-off value for plasma NfL is at 17.2 pg/ml for a sensitivity of 90.3% and specificity of 96.4% (AUC = 0.972), and to differentiate a group of PD patients from a group of PSP/DCB patients, the optimal cut-off value is 16.6 pg/ml with a sensitivity of 88.7% and specificity of 87.8% (AUC = 0.936). This evidence concerns the gene NEFL and multiple system atrophy.