Demographic characteristics and serum NFL levels of the different diagnostic groups
| Diagnostic category | Specific diagnosis | n | M/F | Age | Serum NFL (pg/mL) |
| ALS | 124 | 74/50 | 61 (26–74) | 125 (14.6–908) | |
| Disease controls | See table 2 | 44 | 32/12 | 59.5 (21–86) | 27.3 (0.7–210) |
| Non-neurodegenerative controls | 50 | 23/27 | 54.5 (41–85) | 16.2 (5.4–79.9) | |
| Alzheimer’s disease | 20 | 8/12 | 72 (56–88) | 38.6 (21.6–240) | |
| Frontotemporal dementia | bvFTD | 12 | 8/4 | 61 (52–80) | 46.5 (19.4–103) |
| nfvPPA | 4 | 0/4 | 71 (64–78) | 49.6 (28.2–124) | |
| svPPA | 2 | 2/0 | 61 (56–66) | 53.9 (45.3–62.5) | |
| PPA, not further specified | 2 | 1/1 | 62.5 (59–66) | 76.3 (51.6–101) | |
| Parkinson’s disease | 19 | 12/7 | 70 (42–84) | 27.5 (7.7–81.5) | |
| Creutzfeldt-Jakob disease | 6 | 4/2 | 64 (50–76) | 162.5 (121–288) |
For age and NFL levels, median values are given, with ranges in brackets. Non-neurodegenerative controls are patients without neurodegenerative diseases and without inflammatory diseases of the CNS. ALS, amyotrophic lateral sclerosis; bvFTD, behavioural-variant frontotemporal dementia; NFL, neurofilament light chain; nfvPPA, non-fluent-variant primary progressive aphasia; PPA, primary progressive aphasia; svPPA, semantic-variant primary progressive aphasia.