Cambridgeshire ambulance workers are experimenting with finger-blood tests to diagnose the deadliest form of stroke, with preliminary data showing that they may be twice as effective as relying solely on patients’ symptoms.
These tests work on principles similar to those used to detect co-proofed lateral flow tests (LFTs), and aim to quickly determine whether a person suspected of stroke has suffered a large container occlusion (LVO), where blood clots block the major arteries in the brain.
Although LVO accounts for one-third of strokes, they are responsible for 95% of disability and death. However, if a patient undergoes thrombectomy to manually remove clots within hours of symptoms, the chances of recovery can be significantly improved.
The problem is that only 24 hospitals in the UK can provide thrombectomy treatment, and LVO without brain scans is difficult to diagnose because many other diseases show similar symptoms.
Unless the patient is lucky enough to live near a professional center, it is usually evaluated in a general hospital and then transferred. According to national audit data for 2022-23, it takes an average of three hours or more to arrive at the First Hospital to reach the thrombectomy center.
“Early identification of LVO stroke by ambulance clinicians can provide an opportunity for hospitals whose patients are rapidly tracking their thrombectomy capabilities, avoiding delays in visiting other non-specialized hospitals.
The test consists of two lateral flow cartridges, developed by a Cambridge-based company’s pre-diagnosis, aims to detect two molecules in the blood: the first is a clot-associated protein called d-dimer. The second one is called GFAP, which is related to cerebral hemorrhage. Its absence helps to eliminate blood vessel stroke, rupture of blood vessels and bleeding.
Earlier studies have shown that the kit can detect LVO in 15 minutes with an accuracy of about 90%. This is more than twice the current method used in ambulances, involving inspections [symptoms]”, said Gonzalo Ladreda, the former CEO.
Dr. Louise Flanagan, head of research at the Stroke Association, helped fund early development of the Lvone test, said: “There is about four to six hours window to provide a thrombectomy or thrombolysis when diagnosing a stroke. [where drugs are used to dissolve the clot]but the faster the better.
“Personnel performing a rescuer can do a quick test, which means that the person can provide them with the right treatments faster, which will save brain cells and hopefully limit disability afterward.”
After the newsletter promotion
EEAST is rolling out tests to healthcare workers in South Cambridgeshire to evaluate the feasibility and safety of integrating it into a real-life clinical setting. The data will be submitted to regulators to help assess the applicability of their use within the UK.
The Stroke Association also sponsored a separate trial of a saliva-based stroke test that was recently launched in the West Midlands.
Flanagan said that in addition to saving lives, such testing could also save NHS funds. “In terms of ambulance travel and imaging, there may be cost savings. If the person leaves the hospital with fewer disabilities and fewer side effects, there will also be long-term savings in rehabilitation and social care.”
