It's a first-ever in the world of medicine.

The FDA has approved a breast cancer test kit you can use at home. It marks a small, but significant step toward medicine of the future - diagnosis and treatment tailored specifically to your unique DNA.

But this test has its limits. Our Verify team has some Fast Facts to help you sort it all out.

The kit is from 23andMe - the company known for digging back into your ancestry, using a simple saliva sample.

It costs $199.

You spit into a container and send it in.

23andMe analyzes it and gives you the results.

No doctor or prescription needed.

The test looks for three specific BRCA gene mutations linked to a higher risk of breast cancer. But be aware: Those three mutations are only seen in a small segment of the population.

According to Dr. Emily Drabant Conley, vice president of 23andMe, "They are applicable primarily to people of Ashkenazi Jewish ancestry. So that's an important limitation of the test."

And it's important to keep in mind that there are more than 1,000 other BRCA mutations the test does NOT detect.

Critics worry that this will confuse some users.

"People will misunderstand and believe that because they test negatively, that is, they do not test positive for any of the three BRCA genes that are being tested by the company, that it means they've got a clean bill of health," said David Magnus, a medical ethics professor at Stanford University.

In a nod to that criticism, the FDA's Donald St. Pierre said, "The test should not be used as a substitute for seeing your doctor for cancer screenings or counseling on genetic and lifestyle factors that can increase or decrease cancer risk."

Bottom line: This test can be useful, but only as part of an overall cancer screening regimen. But the test's stamp of approval from the FDA indicates you're going to get reliable information. And it's definitely the wave of the future.

Expect to see more tests like this one over the next few years.