Headspace GC-MS Finds Urinary Mild Traumatic Brain Injury Biomarkers

There is currently no simple test that can reliably detect mild traumatic brain injury (mTBI; such as a concussion), which makes it hard for doctors to diagnose it or track how well someone is recovering. Urine is a promising place to look for clues, since it's easy to collect and reflects what's happening throughout the body. In a recent study, researchers collected urine samples from mice at several points after a mild brain injury (1, 12, 24, 48, and 96 hours later) and analyzed them using headspace gas chromatography-mass spectrometry (GC-MS). A paper based on this research was published in the journal Neurotrama Reports.¹

Why is Diagnosing Concussions So Difficult?

Mild traumatic brain injury, commonly known as a concussion, is incredibly common, especially among teenagers and young adults. But even today, diagnosing it mostly comes down to a doctor's clinical judgment. The problem is that current practice relies heavily on patients describing their own symptoms, and that subjective approach makes it hard to diagnose concussions accurately, predict how someone will recover, and ultimately improve outcomes for patients.² In addition, the broad scoring systems doctors currently use to classify brain injuries, such as the Glasgow Coma Scale, where a concussion is defined as a score of 13 to 15, do not tell doctors much about what's actually happening in the brain or what kind of treatment a patient might need. To address this, the NIH's National Institute of Neurological Disorders and Stroke recently proposed an updated classification system built around four categories: clinical symptoms, biomarkers, imaging, and other modifying factors, aiming to capture a fuller picture of what's going on with each patient.³

A recent review of research into brain injury biomarkers shows just how many different types of biological clues can be found in blood, including proteins, fats, small metabolic molecules, and tiny cell-derived particles called exosomes, all of which can signal that damage has occurred at the cellular or tissue level.⁴ The problem is that drawing blood is invasive, and the laboratory techniques used to analyze it (such as nuclear magnetic resonance [NMR], high-resolution mass spectrometry [HRMS}, and specialized immunoassays) are highly technical, which makes these tools impractical for quick testing, especially outside of a clinical setting.¹

Why Is Urine a Promising Alternative Source for Finding Better Diagnostic Biomarkers?

Unlike blood, urine is easy to work with; special training is not required to collect it, and it does not require complicated processing before it can be analyzed. In earlier research, scientists studying proteins in urine found several markers that dropped in college athletes with concussions (tested within a week of injury) compared to healthy athletes.⁵ Because urine plays such a direct role in how the body processes and gets rid of waste, it is also a great source for studying small molecules related to metabolism. In one study, researchers analyzed urine from young male athletes (collected 1 to 3 days after injury) using proton NMR spectroscopy and found two substances (2-hydroxybutyrate and lactose) that looked promising as possible markers for diagnosing sports-related concussions.⁶ Another study, this one in adults, found that certain amine compounds dropped in the urine following brain injury.⁷

What Did the Study Find in Mice, and Did Those Findings Hold Up in Humans?

In this study, the researchers detected 68 different compounds in the mouse urine samples, and out of those, three stood out as promising leads, as they stayed consistent in the uninjured (control) mice but rose noticeably in the mice with brain injuries. These three compounds were a type of ketone; two of them a specific "unsaturated" kind, and one a "saturated" kind.¹

Based on these mouse findings, the researchers then checked whether similar compounds show up in young people with concussions. Using stored urine samples, they tested 18 patients (ages 7-19) who had suffered a mild traumatic brain injury, along with eight healthy kids as a comparison group, collecting samples anywhere from about 4.5 to 71 hours after the injury. Of the three unsaturated ketones they were looking for, one showed up at significantly higher levels in the kids with concussions compared to the healthy group.¹

“Taken together,” write the authors of the paper,¹ “elevation of urinary ketones in mice and humans suggests acute perturbation of fatty acid metabolism immediately following injury. Thus, ketones could form the basis for an easily accessible human biomarker of mTBI and greatly improve diagnosis and monitoring of these injuries and potentially direct efforts for treatment of mTBI.”

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References

1. Cohen, A.; Arbogast, K. B.; Lee, Y. E. et al. Noninvasive Urinary Biomarkers for Early Diagnosis of Mild Traumatic Brain Injury. Neurotrauma Rep. 2026, 7, 2689288X261464654. DOI: 10.1177/2689288X261464654
2. Patricios, J. S.; Schneider, K. J.; Dvorak, J. et al. Consensus Statement on Concussion in Sport: The 6th International Conference on Concussion in Sport-Amsterdam, October 2022. Br J Sports Med. 2023, 57 (11), 695-711. DOI: 10.1136/bjsports-2023-106898
3. Manley, G. T.; Dams-O'Connor, K.; Alosco, M. L. et al. NIH-NINDS TBI Classification and Nomenclature Initiative. A New Characterisation of Acute Traumatic Brain Injury: The NIH-NINDS TBI Classification and Nomenclature Initiative. Lancet Neurol. 2025, 24 (6), 512-523. DOI: 10.1016/S1474-4422(25)00154-1
4. Kocheril, P. A.; Moore, S. C.; Lenz, K. D. et al. Progress Toward a Multiomic Understanding of Traumatic Brain Injury: A Review. Biomark Insights 2022, 17, 11772719221105145. DOI: 10.1177/11772719221105145
5. Daisy, C. C.; Varinos, S.; Howell, D. R. et al. Proteomic Discovery of Noninvasive Biomarkers Associated With Sport-Related Concussions. Neurology 2022, 98 (2), e186-e198. DOI: 10.1212/WNL.0000000000013001
6. Wanner, Z. R.; Southam, C. G.; Sanghavi, P. et al. Alterations in Urine Metabolomics Following Sport-Related Concussion: A ¹H NMR-Based Analysis. Front Neurol. 2021, 12, 645829. DOI: 10.3389/fneur.2021.645829
7. Bykowski, E. A.; Petersson, J. N.; Dukelow, S. et al. Urinary Metabolomic Signatures as Indicators of Injury Severity Following Traumatic Brain Injury: A Pilot Study. IBRO Neurosci Rep. 2021, 11, 200-206. DOI: 10.1016/j.ibneur.2021.10.003