%0 Journal Article
%T Age-Dependent Differences in Blood Levels of Glial Fibrillary Acidic Protein but Not Ubiquitin Carboxy-Terminal Hydrolase L1 in Children.
%A Mannix R
%A Borglund E
%A Monashefsky A
%A Master C
%A Corwin D
%A Badawy M
%A Thomas DG
%A Reisner A
%J Neurology
%V 103
%N 3
%D 2024 Aug 13
%M 38986044
%F 11.8
%R 10.1212/WNL.0000000000209651
%X <B>OBJECTIVE: </B>Despite the growing evidence of the clinical utility of blood-brain biomarkers in adults with traumatic brain injury (TBI), less is known about the performance of these biomarkers in children. We characterize age-dependent differences in levels of ubiquitin carboxy-terminal hydrolase L1 (UCH-L1) and glial fibrillary acidic protein (GFAP) in children without TBI.<BR><B>METHODS: </B>Plasma biobank specimens from children and adolescents aged 0-<19 years without TBI were obtained, and UCH-L1 and GFAP levels were quantified. The relationship between age and biomarker expression was determined using previously defined aged epochs (<3.5 years, 3.5 years to <11 years, 11 years and older), then biomarker levels were compared with established thresholds for ruling out the need for a head CT in adults with a mild TBI (mTBI) (UCH-L1 400 pg/mL, GFAP 35 pg/mL).<BR><B>RESULTS: </B>The age range of the 366 control patients was 3 months-18 years. There was a significant negative association between age and GFAP but not UCH-L1. Only 1.4% of samples exceeded the UCH-L1 cutoff; however, 20% of samples exceeded the GFAP cutoff and 100% children younger than 3.5 years had values that exceeded the cutoff.<BR><B>CONCLUSIONS: </B>Age seems to modify physiologic plasma GFAP levels. Diagnostic cutoffs for TBI based on GFAP but not UCH-L1 and may need to be adjusted in children younger than 11 years.