Point-of-care prehospital GFAP testing was feasible and demonstrated high diagnostic accuracy in detecting intracranial hemorrhage in adults with acute nontraumatic coma undergoing prehospital RSI.
Key Findings
Results
GFAP demonstrated high sensitivity and discriminatory ability for detecting intracranial hemorrhage in prehospital patients with acute nontraumatic coma.
Sensitivity of GFAP was 97.0% (95% CI, 84.2%-99.9%)
Area under the receiver operating characteristic curve (AUC) for GFAP was 0.94 (95% CI, 0.87-0.99)
Testing was performed using the i-STAT Alinity Point-of-Care Blood Analyzer (Abbott Laboratories) on whole blood
Computed tomography served as the reference standard for ICH diagnosis
Results
UCH-L1 showed lower sensitivity and very limited specificity for detecting intracranial hemorrhage in this prehospital setting.
UCH-L1 sensitivity was 78.8% (95% CI, 61.1%-91.0%)
UCH-L1 specificity was only 18.8% (95% CI, 7.2%-36.4%)
UCH-L1 demonstrated limited overall discriminatory performance compared to GFAP
Results
A combined GFAP and UCH-L1 biomarker approach achieved 100% sensitivity and 100% negative predictive value for intracranial hemorrhage detection.
Combined sensitivity was 100.0% (95% CI, 89.4%-100.0%)
Combined negative predictive value was 100.0% (95% CI, 47.8%-100.0%)
The wide confidence interval on the negative predictive value reflects the small sample size
Methods
The study cohort consisted of 65 adult patients with acute nontraumatic coma presenting with very low Glasgow Coma Scale scores.
Median age was 63 years (IQR, 47-69 years); 55.4% were male
Median GCS score was 4 (IQR, 3-6), indicating severe neurological compromise
All patients underwent prehospital rapid sequence induction (RSI) of anesthesia with clinical suspicion of ICH
Data were collected by a UK physician-paramedic helicopter emergency medical service between January 1, 2025, and April 30, 2026
Patients with traumatic pathology and those without follow-up data were excluded
Results
Intracranial hemorrhage was confirmed in approximately half the cohort, with high rates of neurosurgical intervention and 30-day mortality.
ICH was present in 50.8% of patients (n = 33)
Thirteen patients (20.0%) underwent neurosurgery
The 30-day survival rate was 46.2% (n = 30), indicating a high-acuity population
Patients were observed for up to 30 days from hospital admission
Results
Prehospital point-of-care brain biomarker testing using whole blood was found to be feasible in the helicopter emergency medical service environment.
Testing was conducted in the prehospital setting using the i-STAT Alinity Point-of-Care Blood Analyzer
A consecutive sample design was used to minimize selection bias
The authors note that further prospective external validation is required to determine its association with triage, treatment decisions, and patient outcomes
What This Means
This research suggests that a blood test measuring a brain protein called GFAP (glial fibrillary acidic protein) can be performed at the scene of a medical emergency and may accurately detect bleeding in the brain (intracranial hemorrhage) in patients who are deeply unconscious. The study was conducted by a UK helicopter emergency medical service and included 65 patients who were so unwell they needed to be put under general anesthesia before being taken to hospital. About half of these patients turned out to have a brain bleed confirmed by CT scan, and the GFAP test identified nearly all of them — correctly detecting 97% of brain bleeds and performing even better when combined with a second biomarker called UCH-L1, which together missed none of the confirmed cases.
Currently, paramedics and emergency doctors responding to patients with sudden loss of consciousness have very limited tools to determine whether that person has a brain bleed versus another cause such as a seizure or metabolic problem. This distinction is critical because the treatments differ dramatically and early identification could help route patients to the right hospital faster. This research suggests that a simple finger-prick or blood draw analyzed on a handheld device could provide that information within minutes at the scene, potentially improving triage decisions.
However, the study was small (65 patients) and conducted at a single service, so the results need to be confirmed in larger, independent studies before this test could be routinely adopted. The authors also note that while the test appears diagnostically accurate, further research is needed to determine whether using it actually changes patient outcomes or clinical decision-making in practice.