Every claim on this site traces to a published source. This page lists those sources with a plain-language note on what each one found and what it did not. Entries are dated and updated quarterly.
Last updated: September 2, 2026
1. FDA, De Novo classification DEN170045, Banyan Brain Trauma Indicator (GFAP, UCH-L1), granted Feb 14, 2018. https://www.accessdata.fda.gov/cdrh_docs/pdf17/DEN170045.pdf. The FDA's first authorization of a blood test for evaluating suspected mild TBI, measuring GFAP and UCH-L1. It established that brain-injury proteins in blood can help physicians decide whether a head CT is needed. Boundary: This authorization covers serum testing within 12 hours of injury as an aid to CT decisions in adults. It is not a stand-alone diagnostic for brain injury.
2. FDA, 510(k) K201778, Abbott i-STAT TBI Plasma, Jan 2021. https://www.accessdata.fda.gov/cdrh_docs/pdf20/K201778.pdf. Clearance of a rapid plasma version of the GFAP and UCH-L1 test with results in about 15 minutes. In its supporting study the test showed a negative predictive value above 99 percent for intracranial injury on CT. Boundary: The clearance covers plasma testing within 12 hours of injury for CT-triage purposes.
3. Abbott, FDA clearance of Alinity i TBI lab-based test, Mar 7, 2023. https://abbott.mediaroom.com/2023-03-07-Abbott-Receives-FDA-Clearance-for-First-Commercially-Available-Lab-based-Blood-Test-to-Help-Evaluate-Concussion. Clearance of a core-laboratory version of the test, making it available at hospital-lab scale in serum and plasma. This moved the test from specialized settings into routine laboratory workflows. Boundary: The cleared testing window remained 12 hours from injury.
4. Abbott, FDA clearance of i-STAT TBI whole-blood bedside test, Apr 1, 2024. https://abbott.mediaroom.com/2024-04-01-Abbott-Receives-FDA-Clearance-for-Whole-Blood-Rapid-Test-to-Help-with-Assessment-of-Concussion-at-the-Patients-Bedside. Clearance of a whole-blood version that runs at the patient's bedside in about 15 minutes. The FDA extended the cleared window from 12 to 24 hours with this clearance. Boundary: 24 hours is the outer limit of any FDA-cleared blood-biomarker indication as of this writing. Testing beyond that window is laboratory-developed testing, described on our laboratory standards page.
5. National Academies of Sciences, Engineering, and Medicine. Traumatic Brain Injury: A Roadmap for Accelerating Progress. 2022. https://doi.org/10.17226/25394. The National Academies' comprehensive review of TBI care in the United States. Its first recommendation calls for classification that moves beyond mild, moderate, and severe, incorporates neuroimaging and blood biomarkers where clinically indicated, and is updated as the patient's condition evolves. Boundary: The report endorses no specific commercial test and does not establish diagnostic criteria by itself.
6. NASEM. Biomarkers for Traumatic Brain Injury: Proceedings of a Workshop. 2023. https://nap.nationalacademies.org/catalog/26932. Proceedings of a National Academies workshop on TBI biomarkers across blood, imaging, and electrophysiological classes. It identifies longitudinal biomarker measurement and the understanding of late complications as research priorities. Boundary: The proceedings note that most current evidence concerns the acute phase. We cite this document for the field's direction, not as validation of chronic-phase testing.
7. Manley GT, et al. A new characterisation of acute traumatic brain injury: the NIH-NINDS TBI Classification and Nomenclature Initiative. Lancet Neurology. 2025;24(6):512-523. https://doi.org/10.1016/S1474-4422(25)00154-1. The NIH-NINDS classification initiative's proposed framework characterizing TBI across four pillars: clinical, biomarkers, imaging, and modifiers. It formalizes blood biomarkers as a component of TBI characterization. Boundary: This is a framework for acute TBI characterization, proposed for validation. It is not a chronic-phase diagnostic standard.
8. Silverberg ND, et al. The ACRM Diagnostic Criteria for Mild Traumatic Brain Injury. Arch Phys Med Rehabil. 2023;104(8):1343-1355. https://doi.org/10.1016/j.apmr.2023.03.036. Consensus diagnostic criteria developed by an expert panel for use across civilian, military, and sport settings. Diagnosis is clinical and multi-domain, with elevated blood biomarkers counted among supportive laboratory findings. Boundary: The criteria do not permit diagnosis from a biomarker alone, and they note that biomarker cutoffs and timing are not yet established.
9. Shahim P, et al. Time course and diagnostic utility of NfL, tau, GFAP, and UCH-L1 in subacute and chronic TBI. Neurology. 2020;95(6):e623-e636. https://doi.org/10.1212/WNL.0000000000009985. An NIH cohort followed with serial blood draws from the subacute period out to five years after TBI. Serum NfL remained elevated compared with controls throughout follow-up, and GFAP showed a biphasic pattern, declining over early months and rising again at later visits. Boundary: In this cohort UCH-L1 and tau showed weak associations beyond the acute phase, so this study is not cited for those markers.
10. Newcombe VFJ, et al. Post-acute blood biomarkers and disease progression in traumatic brain injury. Brain. 2022;145(6):2064-2076. https://doi.org/10.1093/brain/awac126. A Cambridge-led cohort with post-acute sampling around eight months after injury. NfL levels predicted later white-matter volume loss, and GFAP showed secondary, temporally distinct elevations up to and beyond five years. Boundary: This is cohort research in largely moderate to severe TBI. It does not establish an individual diagnostic cutoff.
11. Spitz G, et al. Plasma biomarkers in chronic single moderate-severe traumatic brain injury. Brain. 2024;147(11):3690-3701. https://doi.org/10.1093/brain/awae255. Patients a mean of 22 years after a single moderate to severe TBI showed UCH-L1 levels 67 percent higher and phosphorylated tau 181 levels 27 percent higher than matched controls. Those levels correlated with white-matter microstructure and verbal memory. Boundary: GFAP, NfL, and total tau were not elevated in this cohort, and the population was moderate to severe TBI. We cite this study only for UCH-L1 and p-tau181.
12. Hicks AJ, et al. Blood-Based Protein Biomarkers in the Chronic Phase of Traumatic Brain Injury: A Systematic Review. J Neurotrauma. 2025;42(9-10). https://doi.org/10.1089/neu.2024.0294. A systematic review of 30 studies measuring blood protein biomarkers a year or more after TBI. It found reproducible differences between TBI patients and controls in the chronic phase, with the strongest evidence for GFAP after moderate to severe injury and inflammatory markers after mild injury. Boundary: The authors rate the overall strength of chronic-phase evidence as limited and developing.
13. Korley FK, et al. Prognostic value of day-of-injury plasma GFAP and UCH-L1 for predicting functional recovery: TRACK-TBI. Lancet Neurology. 2022;21(9):803-813. https://doi.org/10.1016/S1474-4422(22)00256-3. In the TRACK-TBI cohort, day-of-injury GFAP and UCH-L1 levels predicted six-month functional outcome. The markers carry prognostic information beyond the CT-triage question. Boundary: Samples in this study were drawn on the day of injury.
14. Nelson LD, et al. Recovery after mild traumatic brain injury in patients presenting to US Level I trauma centers: TRACK-TBI. JAMA Neurology. 2019;76(9):1049-1059. https://doi.org/10.1001/jamaneurol.2019.1313. An NIH-funded study following mild TBI patients from 11 US Level I trauma centers. At 12 months, 53 percent reported injury-related functional limitations. Boundary: The cohort is trauma-center patients, a more significantly injured group than all concussion patients, and persistent symptoms in an individual do not by themselves establish structural injury.
15. CDC. Report to Congress on Traumatic Brain Injury in the United States: Epidemiology and Rehabilitation. 2015. https://stacks.cdc.gov/view/cdc/29214. The CDC's report to Congress on TBI epidemiology and rehabilitation. It documents that for a meaningful share of people TBI is the beginning of a long-term condition affecting cognition, mood, sleep, and daily function. Boundary: This is population epidemiology. It does not address diagnostic methods.
16. Mucha A, et al. A Brief Vestibular/Ocular Motor Screening (VOMS) Assessment to Evaluate Concussions. Am J Sports Med. 2014;42(10):2479-2486. https://doi.org/10.1177/0363546514543775. The validation study of the Vestibular/Ocular Motor Screening assessment. Sixty-one percent of concussed patients showed symptom provocation on at least one component, and the combined model identified concussed patients with an area under the curve of 0.89. Boundary: VOMS is a screening adjunct validated in sport-related concussion. It does not diagnose concussion by itself.
17. FDA, 510(k) K181771, RightEye Vision System, Sep 2018. https://www.accessdata.fda.gov/cdrh_docs/pdf18/K181771.pdf. FDA clearance of an eye-tracking system for recording, viewing, and analyzing eye movements in support of identifying visual tracking impairment. It provides objective measurement of eye movements within a clinical evaluation. Boundary: The clearance covers eye-movement measurement only. It does not cover assessing or diagnosing concussion or any brain condition, and we do not describe it that way.
18. Tenney JR, et al. Practice Guideline: Use of Quantitative EEG for the Diagnosis of Mild Traumatic Brain Injury (ACNS). J Clin Neurophysiol. 2021;38(4):287-292. https://doi.org/10.1097/WNP.0000000000000853. The American Clinical Neurophysiology Society's practice guideline on quantitative EEG in mild TBI. It concludes that current evidence does not support the use of qEEG by itself to diagnose mild TBI, classifying the evidence as Level U, meaning insufficient to support or refute. Boundary: We include this guideline because a complete library carries the field's cautions as well as its support. Any EEG-based measure we describe is an adjunct within a clinical evaluation, never a stand-alone diagnostic.
19. Amico F, Koberda JL. Quantitative Electroencephalography Objectivity and Reliability in the Diagnosis and Management of TBI: A Systematic Review. Clin EEG Neurosci. 2023/2025;56(5):432-445. https://doi.org/10.1177/15500594231202265. A systematic review concluding that qEEG can detect functional anomalies after brain injury, including years after the event, while calling for greater standardization. It represents the supportive side of an active professional debate. Boundary: A supportive review does not reverse the ACNS practice guideline above. The two are cited together.
20. Powell JM, et al. Accuracy of mild traumatic brain injury diagnosis. Arch Phys Med Rehabil. 2008;89(8):1550-1555. https://doi.org/10.1016/j.apmr.2007.12.035. At a Level I trauma center, 56 percent of patients who met CDC criteria for mild TBI left the emergency department without a documented TBI diagnosis. The study documented how often mild TBI goes unrecorded in acute settings. Boundary: This is a single-center study of 197 patients, and the finding concerns documentation in the ED record.
21. Cota MR, et al. Discordance between documented criteria and documented diagnosis of traumatic brain injury in the emergency department. J Neurotrauma. 2019;36(8):1335-1342. https://doi.org/10.1089/neu.2018.5772. In a larger cohort of 1,641 patients, only 47 percent of those meeting consensus criteria for TBI received a documented TBI diagnosis in the emergency department. It corroborates the documentation gap at greater scale. Boundary: This is likewise a documentation study, not a study of clinical recognition in every setting.
22. Master CL, et al. Vision diagnoses are common after concussion in adolescents. Clin Pediatr. 2016;55(3):260-267. https://doi.org/10.1177/0009922815594367. Among 100 adolescents aged 11 to 17 evaluated at a specialty concussion clinic, 69 percent had one or more vision diagnoses after concussion, including accommodative disorders, convergence insufficiency, and saccadic dysfunction. Boundary: The population is adolescents referred to a specialty clinic. The figure does not generalize to adults or to unselected concussion populations.
23. Yue JK, et al. Association between plasma GFAP and MRI abnormalities in patients with CT-negative TBI: TRACK-TBI. Lancet Neurology. 2019;18(10):953-961. https://doi.org/10.1016/S1474-4422(19)30282-0. In the multicenter TRACK-TBI study, 27 percent of TBI patients with a normal head CT had visible traumatic abnormalities on MRI two weeks later. Plasma GFAP distinguished the MRI-positive patients with an area under the curve of 0.78. Boundary: This is a research cohort finding. It supports the limits of CT and the informativeness of GFAP, not an individual diagnostic threshold.
24. Undén J, Romner B. Can low serum levels of S100B predict normal CT findings in head injury patients? Eur J Emerg Med. 2010. https://doi.org/10.1097/MEJ.0b013e3283329b63. A study of whether low serum S100B levels can predict normal CT findings after head injury. It supports S100B's role as an acute screening marker, a use adopted in several European guidelines. Boundary: The context is acute screening to reduce unnecessary CT scans.
25. Thelin EP, et al. A review of the clinical utility of serum S100B protein levels in the assessment of traumatic brain injury. Acta Neurochir. 2017. https://doi.org/10.1007/s00701-016-3046-3. A review of the clinical utility of serum S100B in TBI assessment across settings and time points. It summarizes both the marker's strengths and its interpretive limits. Boundary: S100B is also released from sources outside the brain, which is one reason no single marker is interpreted in isolation.