By avoiding the need for time-consuming scans, it means treatment to reduce permanent brain damage can begin earlier, ie, in the ambulance before the patient arrives at hospital.
The device, which is similar to those used by people with diabetes, is being trialled on 375 National Health Service patients and could be approved for use in hospitals by early next year.
The blood test, SmartChip, checks compounds called purines which are produced by cells when deprived of oxygen as occurs in ischaemic stroke, where clots stop the blood supply.
Roughly 85% of strokes are ischaemic stroke: the remainder are haemorrhagic, caused by bleeds in the brain as a result of a burst blood vessel.
During the initial stage of a stroke, approximately two million brain cells die every minute, so the faster the oxygen supply can be restored, the more of the brain can be saved.
One of the challenges for doctors and paramedics is determining the type of stroke and diagnosing it, based on symptoms which overlap with other conditions such as seizures or brain tumours.
Paramedics look for signs such as facial drooping, arm weakness and speech difficulties but sometimes other conditions can be mistaken for strokes, or real strokes may be missed.
Ischaemic stroke is treated with clot-busting drugs. If given in 30 minutes, the chance of full recovery can be as high as 90%. But this falls to around 50% three hours later.
Haemorrhagic strokes are treated with drugs that allow the blood to clot, so it’s critical the type is determined quickly to allow effective treatment. This involves a CT or MRI scan in hospital, which can take hours, losing precious time.
If a stroke is suspected, a finger-prick drop of blood from the patient is added to a disposable strip.
This is inserted into a hand-held reader which displays purine levels within three to five minutes.
Early results from the trial show much higher levels in ischaemic stroke patients compared to healthy people. They also show that the higher the level, the greater the amount of brain tissue affected by the stroke. These results can be used to guide treatment.
“The use of rapid blood tests to identify patients with stroke is a very important and exciting area of research, and the results of this trial are awaited with keen interest,” Dr Richard Perry, a consultant neurologist at University College London Hospitals, said.
“Purine released into blood seems a good potential candidate for identifying an acute brain injury, but it’s unclear if it can distinguish between blockage and rupture of an artery as a cause.
“These two types of strokes require very different treatment strategies, so distinguishing them early is another important goal for blood biomarker studies.”
Meanwhile, being overweight or even mildly obese could boost your chances of surviving a stroke, researchers at Boston University School of Medicine said.
They monitored almost 800 people for 10 years after a stroke and found those who were overweight or mildly obese (with a BMI of 25 or more) had better survival compared to those of normal weight. - Daily Mail