Scammers are offering "free" genetic tests and claiming Medicare will cover it.

But don't fall for this scam.

The scammers are doing this so they can get your Medicare number and use it to commit fraud and identity theft, says a recent government warning. They're targeting people through telemarketing calls, health fairs, and even knocking on doors, according to Medicare.gov.

Uncle Sam says only a doctor you know and trust should order and approve any requests for genetic testing. "If Medicare is billed for a test or screening that wasn't medically necessary and/or wasn't ordered by your doctor, the claim could be denied," Medicare officials warn. That means you could be responsible for the entire cost of the test, which could be thousands of dollars.

Here's how to protect yourself:

  • Don't share your Medicare number, Social Security number, or other personal information with anyone who offers to give you a "free" in-person genetic screening or cheek swab, or a DNA testing kit in the mail.
  • If you get a genetic testing kit in the mail, refuse the delivery or return to sender -- unless your doctor ordered it.
  • If you suspect Medicare fraud, call 1-800-MEDICARE.

Learn more from the U.S. Department of Health and Human Services at Fraud Alert: Genetic Testing Scam.

Got questions about the new tax law, Social Security, retirement and/or investments? Email

Robert.Powell@TheStreet.com

.