A controversial test which could be used to estimate how long people have left to live will go on sale to the general public in Britain later this year, The Independent reported Monday.

The $703 blood test measures vital structures on the tips of a person's chromosomes, called telomeres, which indicate how fast a person is aging.

Scientists believe the test can show whether a person's "biological age" is older or younger than their actual chronological age.

"We know that people who are born with shorter telomeres than normal also have a shorter lifespan," said Dr. Maria Blasco, of the Spanish National Cancer Research Centre in Madrid, who is behind the new commercial telomere test.

Blasco's company, Life Length, is in talks with medical diagnostic companies across Europe to market the test and is anticipating an increasing number of clients as the cost of the test goes down.

Professor Jerry Shay, of the University of Texas Southwestern Medical Center in Dallas, who is also a scientific consultant for Life Length, said the test would certainly appeal to many people.
"I think people are just basically curious about their own mortality. If you ask people what they worry about, most people would say they are worried about dying," he said.

He added, "People might say 'If I know I'm going to die in 10 years I'll spend all my money now,' or 'If I'm going to live for 40 more years I'll be more conservative in my lifestyle.'"

However, while Telomere testing is expected to become widespread within the next five or 10 years, there are already concerns over its value and ethics.

Carol Greider, of Harvard Medical School, recently told the journal Science, "Do I think it's useful to have a bunch of companies offering to measure telomere length so people can find out how old they are? No."

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