California ? Doctors soon may be employing a simple blood test to help them determine which heart patients are at greatest risk for heart attack, stroke and death.

The test has been used for years in hospital emergency rooms to confirm a diagnosis of heart failure. And it’s now proved to be an excellent predictor of the severe consequences of heart disease, even when other, more routine tests are negative.

Findings from the University of California, San Francisco, will not immediately change the way patients with symptoms of heart trouble are assessed but may eventually play a key role in guiding doctors to treatment decisions.

The study was published in Tuesday’s issue of the Journal of the American Medical Association.

An estimated 71 million Americans have some form of cardiovascular disease. It remains the leading cause of death in the United States.

The blood test, which takes less than an hour to complete, measures levels of a substance known cryptically as N-terminal fragment of the prohormone brain-type natriuretic peptide, or NT-proBNP.