When Will I Die? Scientists Develop New Blood Test That Could Reveal Life Expectancy

Scientists have developed a blood test that measures a person's biological age. Getty Images

Life is short, the saying goes, and exactly how much time we have before we shuffle off this mortal coil is anyone's guess. But this uncertainty could be consigned to history, according to the creators of a blood test they claim can predict a person's life expectancy.

The test measures what the scientists at Yale University call a person's "phenotypic age," The Guardian reported. Put simply, if a person's phenotypic age is higher than their chronological age, they may be at greater risk of dying. It works by measuring nine biomarkers in the body, the authors wrote in a paper published in the biological sciences archive bioRxiv. The paper was not peer-reviewed.

Dr. Morgan Levine, assistant professor of pathology at Yale School of Medicine, explained to The Guardian the test can identify differences in life expectancy among individuals who are seemingly healthy.

The team defined "healthy" as being free of disease and having a normal BMI.

"It's [the test] picking up how old you look physiologically," Levine told the newspaper. "Maybe you're 65 years old but physiologically you look more like a 70-year-old, so your mortality risk is more like that of a 70-year-old."

A clinician could therefore use the results as the basis for personalized lifestyle advice on how to prevent diseases and raise a patient's life expectancy, she said.

To develop the test, the researchers analyzed 42 clinical measures documented in participants of the U.S. National Health and Nutrition Examination Survey (NHANES). Factors such as their lifestyle and medical history were recorded, as well as a cause of death where relevant. The measures included glucose levels, white blood cell count and levels of albumin, a protein made by the liver.

The study included data on 10,000 people collected between 1988 to 1994. This information enabled scientists to create a test homing in on nine biomarkers. The method was validated in 11,000 participants of a second study running from 1999 to 2010.

Read more: Five Healthy Habits That Could Boost Life Expectancy by Almost 15 Years Identified in Harvard Study

"Phenotypic age was significantly associated with all-cause mortality and cause-specific mortality," the authors wrote.

Every year a person's phenotypic age was above their real age, their risk of dying rose by 14 percent in those between 20 to 39 years old; 10 percent in the 40- to 65-year-old category, and 8 percent among 65 to 84 year olds. Overall, people who aged fastest had more diseases than those who aged at a slower pace.

The test can also differentiate among individuals who appear to be healthy, and "who may have otherwise been missed using traditional health assessments," the authors wrote.

It is unclear if and when the test will be rolled out in the general population. Yale University did not immediately respond to a request for comment.

Levine told The Guardian the team hopes the test will help "the majority of the population who are middle-aged, who don't have things wrong with them."