NEFL and brain injury: While the specific triggers for NfL production are not fully understood, it is known that various pathological processes affecting neurons, such as neurodegenerative diseases (Rosengren et al., 1996; Gaiottino et al., 2013; Khalil et al., 2018; Gaetani et al., 2019), traumatic brain injury (Snowdon et al., 1997; Thelin et al., 2017), or neuronal damage (Strydom et al., 2018), can lead to increased production and the release of NfL into the surrounding tissues and blood.