If we can find a way of spotting who is at risk, they could be prioritised

Dr Nick Verrall, Cardiothoracic Centre

However, it is possible that, if it proves an accurate way of predicting heart trouble, that it could be offered more widely as a screening test.

Dr Nick Verrall, who is running the clinical trial, told BBC News Online: "The problem with coronary artery disease is that it can be quite unpredictable.

"Some patients may have the disease for many years with few major problems, while others have to be admitted to hospital frequently, or suffer major events such as heart attacks.

Protein giveaway

"If we can find a way of spotting who is at risk, they could be prioritised.

"We think that the test that has been developed will show us the people who are at between three and five times higher risk of having a heart attack."

The test, developed by Dr Cheng Toh at the Royal Liverpool Hospital, detects levels of a particular type of a body chemical called c-reactive protein.

C-reactive protein in general is linked to inflamed tissues in the body, and elevated levels may happen as a result of fighting a chronic infection.

This type of inflammation is thought by many doctors to be a contributory factor in the damage to the heart's blood vessels which can clog them up and eventually cause an attack.

The particular type of c-reactive protein spotted by the test binds to fat in the bloodstream called cholesterol, and there is some evidence it has a role in artery clogging.

The two-year study has been funded by a �40,000 cash donation from the family of a local woman.