A Finger-Prick Blood Test Could Save Stroke Patients' Lives—Here's How

A groundbreaking fingerstick blood test can now identify Large Vessel Occlusion (LVO) strokes—the deadliest type—in under 10 minutes using only a drop of blood, potentially preventing permanent disability by enabling faster treatment. The test, called LVOne, measures two key biomarkers and requires no laboratory equipment or specialist training, making it usable in ambulances, helicopters, and even remote offshore platforms.

Why Every Minute Matters in Stroke Care?

Stroke is a leading cause of death and disability worldwide, but one of its most devastating subtypes—Large Vessel Occlusion stroke—often goes undetected until patients arrive at the wrong hospital. Currently, patients are typically taken to the nearest local hospital, diagnosed via CT scan, and then transferred to a specialist center for treatment. This second transfer costs an average of 120 minutes, during which millions of neurons die.

"For every minute a stroke goes untreated, a patient loses approximately 1.9 million neurons," explains Gonzalo Ladreda, CEO and Founder of Upfront diagnostics, the Cambridge-based company that developed LVOne. The math is sobering: saving 97 minutes translates into a significantly higher likelihood that a patient will walk out of the hospital rather than require lifelong nursing care, potentially saving healthcare systems billions in long-term disability costs.

How Does LVOne Actually Work?

LVOne uses a lateral flow format—similar to a rapid COVID-19 or pregnancy test—that measures two clinically validated biomarkers: Glial Fibrillary Acidic Protein (GFAP) and D-dimer. GFAP is a highly specific marker for brain hemorrhage, while D-dimer indicates active clot formation. Both were identified in independent systematic reviews as the best markers for pre-hospital stroke diagnosis.

The test requires only a drop of capillary blood obtained from a fingerstick, delivers results in under 10 minutes, and needs no complex equipment or specialized training. This simplicity is intentional—the device was engineered specifically for the hostile environment of an ambulance, helicopter, or remote location where traditional diagnostic tools are unavailable.

Steps to Implementing Rapid Stroke Diagnostics in Emergency Care

• Clinical Validation: LVOne was validated across six National Health Service (NHS) stroke hospitals with over 500 patients, proving the test works reliably in real-world emergency settings before widespread adoption.
• Workflow Integration: The diagnostic must fit seamlessly into existing emergency protocols without adding complexity or burden to ambulance crews, making it "invisible" to the workflow while providing critical information.
• Environmental Testing: The device must perform reliably in extreme conditions—from ambulances to helicopters to offshore platforms—ensuring stability at room temperature and portability in handheld form.

Where Is LVOne Being Tested Right Now?

Upfront diagnostics has expanded testing to some of the world's most challenging pre-hospital environments. In Puerto Rico, the COPILOT trial demonstrated that demand for rapid diagnostics is highest where infrastructure is most strained. In underserved or geographically isolated systems, the distance to a CT scanner can be hours, making a portable blood test a genuine equalizer that gives a rural paramedic insights similar to those of a doctor in a major metropolitan hospital.

Even more remarkably, Johanniter Offshore Rescue is currently trialling LVOne with crews operating over the North and Baltic Seas, reaching patients on offshore platforms, ships, and wind turbines miles from the nearest hospital. These are environments where there is no CT scanner within reach and no rapid transfer to a stroke center possible. The fact that LVOne performs reliably in these extreme conditions speaks to the robustness of the design and points to where rapid stroke diagnostics could expand next: anywhere a paramedic can reach.

Beyond Stroke: Expanding to Brain Injuries

Upfront diagnostics has partnered with Harvard, MIT, Oxford, and Cambridge to trial the first Glial Fibrillary Acidic Protein lateral flow device for traumatic brain injury (TBI)—a condition that includes concussions from sports, car accidents, and falls. The same core biomarker platform that enables pre-hospital stroke triage can be applied wherever rapid neurological assessment is needed, expanding the clinical need far beyond stroke alone.

As Upfront diagnostics advances toward commercialization, the team is focused on bringing LVOne to emergency services across the UK, Europe, and beyond. The vision is clear: rapid stroke diagnostics that can reach patients anywhere in the world, transforming how emergency responders identify and treat one of medicine's most time-sensitive conditions.