Blood tests are used to detect everything from infections to cardiac injury — but what about concussions?
Over the past decade, researchers have been exploring blood-based biomarkers to help diagnose or monitor mild traumatic brain injury (mTBI). The goal? Find a reliable, objective test that can confirm a concussion and guide return-to-play or return-to-learn decisions.
But are we there yet? Not quite.
Let’s explore what the science says.
🔬 What Are Concussion Biomarkers?
When the brain is injured, certain proteins may leak from brain tissue into the bloodstream. These proteins — or biomarkers — can then be measured in blood tests to evaluate whether an injury occurred, and how severe it might be.
Some of the most studied biomarkers in concussion research include:
- S100B: A calcium-binding protein released by astrocytes
- GFAP (Glial Fibrillary Acidic Protein): Expressed after glial cell injury
- UCH-L1: A neuronal enzyme involved in protein breakdown
- Tau and Neurofilament Light (NfL): Axonal injury indicators
These molecules can appear in the blood within minutes to hours of impact and may remain elevated for days to weeks.
🧪 So… Can a Blood Test Diagnose a Concussion?
The short answer: Not reliably.
While these biomarkers can reflect brain injury, their real-world use is still limited by:
- Sensitivity and specificity issues (false positives/negatives)
- Timing variability (elevations may appear too early or too late)
- Lack of standardization between labs and devices
Currently, blood tests like GFAP and UCH-L1 are approved by the FDA only to rule out intracranial bleeding on CT scans — not to diagnose concussion (1).
In other words, they can help exclude serious structural injury, but not confirm a functional one like mTBI.
📉 Why Clinical Assessment Still Leads the Way
Because concussion is a functional brain injury, diagnosis is still based primarily on:
- Symptom reports
- Clinical evaluations (SCAT6, SCOAT6)
- Cognitive, balance, and vision testing (VOMS, BCTT, etc.)
📋 How to Know If You Have a Concussion
For now, clinical tools outperform blood tests when it comes to:
- Identifying persistent symptoms
- Guiding rehabilitation strategies
- Supporting safe return to play
⚠️ The Risk of Over-Reliance on Biomarkers
Blood-based diagnostics are exciting — but they shouldn’t replace clinical care.
Over-reliance could:
- Delay proper assessments if a biomarker appears “normal”
- Miss symptoms that require targeted rehab (vestibular, cervical, vision)
- Provide false reassurance and lead to premature return to sport
📘 Top 5 Most Effective Treatments for Persistent Concussion Symptoms
🧠 Where Do We Go From Here?
Blood tests may one day support concussion diagnosis — but they’re not there yet. The most effective way to manage concussion today is still:
- Objective baseline testing before injury
- Early multidisciplinary assessment after injury
- Symptom-specific, progressive rehabilitation
📲 Use Our App to Track Baseline and Post-Injury Data
🏥 Find a Certified Concussion Clinic Near You
References
- Papa L, et al. Use of serum biomarkers in the evaluation of traumatic brain injury: FDA approval and future directions. Clin Chem. 2021;67(1):52–63.
- Shahim P, et al. Blood biomarkers for brain injury in concussed athletes. JAMA Neurol. 2014;71(7): 932–940.
- Zetterberg H, Blennow K. Fluid biomarkers for mild traumatic brain injury and related conditions. Nat Rev Neurol. 2016;12(10):563–574.