A cheap blood test could save lives of thousands of heart attack patients, according to a new study.

The British Heart Foundation (BHF), which funded the work, said the quick test can help doctors to spot people at high risk of death following a suspected attack.

In the largest study of its kind, researchers found that measuring levels of high sensitivity C-reactive protein (CRP) – a known sign of inflammation – in the blood of people after a heart attack can help pinpoint whether they are at risk of dying in the next three years.

The blood test, which is already used in hospitals to diagnose other conditions, may help inform choices, with those at the highest risk closely monitored and given more intensive treatment, the BHF said.

At the moment, when doctors think a person has had a heart attack, they perform a blood test for troponin, a protein that is released into the blood stream when the heart is damaged.

Now, scientists have found that measuring CRP levels at the same time provides a detailed picture.

For the study, published in the journal Plos Medicine, researchers used data from more than 250,000 patients who were admitted to hospital with a suspected heart attack.

Normally, the level of CRP in the blood is 2 mg/L or under.

However, the research found that a raised measurement of 10-15 mg/L CRP in those with a positive troponin test predicted an over 35% increased risk of death three years later.

The work was carried out by experts from Imperial College London in collaboration with the National Institute for Health Research (NIHR) Health Informatics Collaborative (HIC).

Dr Ramzi Khamis, from Imperial College London, said: “Testing for this biological ‘red flag’ at the same time as other hospital tests identifies those more vulnerable patients who should be receiving closer medical attention.

“Importantly, we hope with more research, we can be successful in developing new therapies that specifically combat inflammation to improve outcomes in heart disease.”

One of the therapies that could be tested as a potential treatment is the anti-inflammatory drug colchicine, which is known to be effective against atherosclerosis (the build-up of fatty deposits in the arteries).

Professor James Leiper, associate medical director at the BHF, said: “Every five minutes, someone is admitted to a UK hospital with a heart attack, and it is estimated that there are 1.4 million people in the UK who have survived a heart attack.

“This test presents a valuable new tool in doctors’ arsenal to direct quick and effective care for the millions of heart attack patients.

“By better identifying which people are most at risk, this simple blood test could help to direct anti-inflammatory treatments to those who most need it.”