A simple blood test could rule out heart attacks in patients complaining of chest pain, the Press Association reports.
Researchers said the high sensitivity test could rule out a heart attack diagnosis in nearly two thirds of people who arrive at accident and emergency (A&E) departments, meaning they could be sent home without needing to be admitted.
Acute chest pain is one of the most common causes of hospital admissions and is responsible for one million visits to A&E wards in the UK, according to the study published in the Lancet medical journal.
The test measures a protein called troponin in the patient's blood, with low levels suggesting they are at "very low risk" of an attack within the following 30 days.
Lead author Dr Anoop Shah from the University of Edinburgh, said: "Until now there were no quick ways to rule out a heart attack within the emergency department.
"Over the last two decades the number of hospital admissions due to chest pain has tripled. The overwhelming majority of these patients do not have a heart attack.
"We have identified a cardiac troponin concentration below which patients are at very low risk of heart attack either during the admission or in the ensuing 30 days.
"These patients are therefore potentially suitable for immediate and safe discharge from the emergency department. These findings could dramatically reduce unnecessary hospital admissions and provide substantial cost savings for healthcare providers."
The study, funded by the British Heart Foundation, used the test to measure troponin levels in more than 6,000 patients at four hospitals in Scotland and the US. It found 61% of people had a troponin concentration of less than five nanograms per decilitre - meaning there was a 99.6% likelihood they were at minimal risk of an attack.