A New Blood Test Predicts How Long You'll Live

But would you want to know?

November 19, 2013

If there was a simple, accurate test that could predict whether you’ll die from heart disease—and early enough so you could make changes to alter the outcome—would you take it? Of course you would. And you probably already have. Called the complete blood count risk score, or CBC, it’s been used routinely by physicians for years to get an overall picture of your health—and now a new study shows that an oft-overlooked measure of that test can accurately predict whether you'll succomb to cardiovascular disease.  

Researchers from Intermountain Medical Center in Murray, Utah, and Harvard’s Brigham and Women’s Hospital in Boston followed more than 17,000 men and women for five years as part of a larger clinical trial involving a cholesterol-lowering drug. They discovered that participants with high levels of a measure called "red cell distribution width" (RDW) were twice as likely to die compared to those with low RDW levels. 


Normally, doctors only look at RDW counts when trying to pinpoint very specific diseases, like certain types of anemia. “But it has turned out to be one of the most predictive factors of cardiovascular events and mortality. Peer reviewers actually thought it was too good to be true, because the CBC had been around for 50 years,” says study author Benjamin Horne, PhD, director of cardiovascular and genetic epidemiology at the Intermountain Medical Center Heart Institute.

Why a high RDW indicates future heart problems, though, is still a mystery. “It could have to do with red blood cells being produced erratically or too quickly, or it could be that there’s a microvascular disease where red blood cells are being torn up in the blood vessels,” Dr. Horne says. 

What is known for sure? The test is an accurate one, and in the not-too-distant future, your doctor could be using it to determine your risk. “We’re working to examine whether the RDW can potentially be used to predict what [cardiovascular events] individuals will experience in the future, and make some smaller changes now that will have a bigger effect on preventing cardiovascular disease rather than waiting until they actually have the disease,” says Dr. Horne. 

More from Prevention: How To Keep Heart Disease Out Of Your Future

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