Can a Blood Test Determine How Long People Will Live?

Need to Use Data Carefully

One of the problems that could arise from this test is the misuse of information. If the test becomes more widely available, people need to make sure they purchase it from a reputable company.

"This is likely to spur a whole bunch of snake oil," said Shay, meaning unscrupulous companies selling the test could also try and sell other items purported to offer longevity or other false benefits.

People also need to be sure insurance companies don't get hold of the data.

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"If it's found you have shorter telomeres, companies may look at that and start charging higher rates," Shay said.

While it's important to protect people's results, Evans doesn't think the test poses any real ethical concerns.

"I don't think it will cause any dramatic harm to people who have the test done," he said.

Until more is known about what life span secrets the telomere holds, Evans believes people should focus on more important ways to reliably increase longevity.

"The things that matter are not smoking, drinking in moderation, exercising, eating a reasonable diet, maintaining a reasonable weight and wearing a seat belt," he said. "This is the vast bulk of things you can alter to increase your life span."

Additional reporting by ABC News' Jane Kurtzman and Bojana Zupan.