As such, a limitation of the procedure listed on the Banyan BTI Package Insert describes that because of the cross‐reactivity of neurofilament light (NfL) with the antibodies in the Banyan GFAP Kit, patients with neurodegenerative diseases such as Guillain‐Barré syndrome, ALS, PD, AD, or Creutzfeldt‐Jakob disease may have erroneously high Banyan GFAP, hence a false‐positive result. This evidence concerns the gene GFAP and Parkinson disease.