* More sensitive test looks for signs of heart injury
* Blood test could be used to guide treatment
CHICAGO, Dec 7 (Reuters) - A new blood test may be able to tell whether a seemingly healthy person is at risk of dying from heart disease, U.S. researchers said on Tuesday.
An older, less sensitive version of the test detects a certain protein in only a small percentage of people, but a study of the newer test made by Roche (ROG.VX) found it in about 25 percent of 3,500 blood samples.
And people who had detectable levels of the protein, released by damaged heart muscle, were nearly seven times more likely to die of heart disease within six years.
Both tests look for a protein called cardiac troponin T, which indicates muscle damage in the heart, but the newer test called Elecsys Troponin T is 10 times more sensitive.
"This test is among the most powerful predictors of death in the general population we've seen so far," said Dr. James de Lemos of the University of Texas Southwestern Medical Center in Dallas, whose study appears in the Journal of the American Medical Association.
"It appears that the higher your troponin T, the more likely you are to have problems with your heart, and the worse you're going to do, regardless of your other risk factors," he said in a statement.
Currently, tests that look for troponin T are used in emergency departments to see if a person with chest pain is having a heart attack.
But de Lemos thinks the new test could be used as part of a routine checkup to look for signs of heart damage that might be treated or reversed with drugs or lifestyle changes.
For the study, the team gave the standard and the more sensitive test to 3,500 people of different races in Dallas County between 2000 and 2002, then followed them through 2007.
People aged 30 to 65 were grouped into five categories based on their troponin T levels. The team used magnetic resonance imaging or MRI scans to look at the structure and function of the heart, as well as other tests to look for signs of heart disease.
They could detect cardiac troponin T in 25 percent of adults using the newer test, but in fewer than 1 percent using the standard test.
Men were three times more likely to have detectable levels than women, and blacks were far more likely than Hispanics or whites to have detectable levels of the protein.
"This is a really very powerful correlation with premature death in African Americans," de Lemos said in a telephone interview.
In the Dallas area, blacks typically have more thickening of the heart muscle in whites, and treating this might help prevent more deaths from heart disease.
De Lemos said the study points to new uses for the Roche test, which is currently approved in Europe but not in the United States. He said the test could be used with other factors to predict which patients are at risk for dying from heart disease.
"It also identifies people who have things that could be treated today," he said.