The laboratory diagnosis and follow up of NICTH heavily relies on the finding of a relatively high concentration of big IGF in the patient's circulation with suppressed levels of insulin, C‐peptide, IGF‐I, and ALS.18, 87 In several case reports an enhanced ratio between (total) IGF‐II and IGF‐I immunoreactivities in serum, as determined by RIAs or ELISAs, has been used as a surrogate biomarker for NICTH. This evidence concerns the gene IGF1 and amyotrophic lateral sclerosis.