A new blood test that speeds up the diagnosis of heart attacks could save the NHS millions of pounds every year and cut waiting times in A&E, according to new research.
The new test is much more accurate than the one currently used and could free up doctors' time and NHS beds.
Research suggests that more than two-thirds of people who go to A&E with chest pain have not had a heart attack.
Despite this all of these patients undergo a blood test when they arrive at accident and emergency and again three hours later to detect any possible damage to the heart muscle.
The test that is currently used works by analysing biomarkers, including cardiac troponin. Those with undetectable levels of cardiac troponin are classified as low risk and are discharged from hospital.
However, thousands of patients fall into an intermediate risk group - up to 85% of all patients - and require an overnight stay and further blood tests.
The new test developed by scientists from King's College London looks for another biomarker - cardiac myosin-binding protein C (cMyC) - which is even more sensitive at detecting damage to the heart muscle.
Levels of cMyC in the blood increase more rapidly after a heart attack, and to a higher extent, than troponin.
The new test - which could be rolled out across the NHS in the next five years - can therefore lead to a much more rapid diagnosis.
The study on more than 2,000 people at hospitals in Switzerland, Italy and Spain was funded by the British Heart Foundation (BHF) and published in the journal Circulation.
The results showed that compared to the troponin test, the new test doubled the number of patients found not to be having a heart attack.
Experts calculated that just one UK hospital - St Thomas' in London, which carries out 7,800 heart attack tests each year - could save £800,000 a year by reducing admissions and freeing up beds.
One of the researchers in the study, professor Mike Marber said: "We've shown that this test is not only just as good as the current test for working out who has had a heart attack, but it's also much better at working out who hasn't.
Dr Tom Kaier, one of the lead researchers from St Thomas', said: "We often see patients in hospital who have to stay for further tests as a result of a mildly abnormal blood test - this is stressful and often unnecessary.
"Our research shows that the new test has the potential to reassure many thousands more patients with a single test, improving their experience and freeing up valuable hospital beds in A&E departments and wards across the country."
Professor Sir Nilesh Samani, medical director at the BHF, said more research was needed before the new test could completely replace the troponin test.