(WTNH) — It’s a simple test you can do right now, and it could save your life.

According to a Yale News report, aortic aneurysms are the 13th most common cause of U.S. deaths. They kill about 10,000 people each year and affect adults of all ages.

But a Yale study found that you can conduct your own test using the thumb and palm of one hand to assess your risk of having an aortic aneurysm.

Just stick out your hand like you’re telling someone to stop, and then see how far your thumb can stretch across your palm. If your thumb reaches all the way past the far side of your palm, you may be at risk.

That test saved the lives of Heather and Crystal Gagnon.

A couple of years ago, Heather Gagnon had some health issues and got checked by Dr. John Elefteriades, an aorta specialist at Yale New Haven Hospital.

“So he says, ‘Sit up on the table.’ and he goes, ‘I’m going to do a test on you.’ I’m like, ‘Okay, what?’ and he goes, ‘Just do this,'” Heather explained, holding up her hand and stretching her thumb completely across her palm.

“He goes, ‘Yup, that’s a strong positive,'” she said. “And I was like, ‘What is this?'”

The thumb-palm test is all about collagen, which holds our organs together. If your thumb reaches all the way past the far side of your palm, the collagen in your hand may be deficient.

“The collagen in the aorta is also deficient,” said Elefteriades. “So because it’s deficient, the aorta can stretch, and as it stretches like a balloon, it can rupture.”

The condition is known as an aortic aneurysm, and Elefteriades said they are more common than we used to think.

He said they can happen with no warning, adding that “95% of patients don’t have an inkling of any kind until the aorta ruptures and they die.”

Only 5% to 10% of people with aortic aneurysms have symptoms before dissection or rupture, Yale News reported.

Tests showed Heather Gagnon had an aneurysm, and she got surgery after Elefteriades gave her the thumb-palm test. Her twin sister, Crystal, also tried it and later found the same issue with her aorta. She had the surgery as well.

“We both shouldn’t be here right now because there were no symptoms at all from it,” Heather Gagnon said.

The twins say they are doing great now, which is the case with most people with aneurysms if the condition is found in advance.

“Just a quick thing that your doctor can do,” said Crystal Gagnon. “It can see it saving lives.”

Now, don’t panic if your thumb stretches across your hand. The thumb-palm test is not a guarantee that you have an aneurysm, and not all aneurysm patients have “stretchy” thumbs.

“Only a minority of patients with aneurysms have a positive test,” said Elefteriades. “If you have a positive test, you’re in an enriched group with a high degree of aneurysms.”

Just mention the test to your doctor. Heather and Crystal Gagnon are certainly glad they heard about it.

“Another year, she and I shouldn’t be here right now,” Heather Gagnon said. “So we’re blessed. Definitely.”