While sitting at home on a Sunday afternoon, I received an email from a concerned friend asking about a potential Medicare scam. Their mother had received a call from someone claiming to be from Medicare who was offering to provide some free medical equipment. All that was needed to complete the transaction was a Medicare number. I quickly replied that no one from Medicare would ever call and ask you to provide your Medicare number.

Health care fraud has many faces, and criminals are becoming more sophisticated in their efforts to scam the system. Although it is rare, the most troubling cases involve medical professionals - the same individuals with whom we entrust our care. The vast majority of providers are honest; however, the very small percentage that are not can cost taxpayers billions of dollars and put beneficiaries' well-being at risk. Health care fraud drives up costs for everyone and endangers the future of programs more than 100 million Americans depend on every day.

Maintaining the integrity of the Medicare program is a top priority for the Centers for Medicare and Medicaid Services (CMS). With our law-enforcement partners, we have put in place a set of comprehensive measures to fight fraud and abuse, and our efforts are paying off. In 2011, together, we recovered a record $4.1 billion.

Providers and suppliers who want to participate in Medicare must now pass a tougher set of screening procedures. High-risk categories of providers and suppliers receive additional scrutiny before they're able to bill Medicare, Medicaid and the Children's Health Insurance Program (CHIP). CMS also has new authority to suspend payments during fraud investigations.

New penalties for individuals engaging in Medicare abuse reflect the seriousness of the crimes with sentences between 20 percent and 50 percent longer for the worst offenses. From 2008 to 2011, there has been a 75 percent increase in individuals charged with criminal health care fraud.

CMS has also implemented a new Fraud Prevention System that uses predictive modeling technology, similar to the technology that credit card companies use to flag suspicious activity, to review claims before they are paid. Since the technology was first introduced in 2011, all Part A and B Medicare claims - over one billion - have run through the system. During the first year, the system initiated 536 new investigations and helped stop, prevent, or identify an estimated $115 million in fraudulent payments.

But our most important ally in the fight against fraud is you. Here are a few ways you can guard your benefits and join us in the fight against fraud:

• Guard your Medicare number. Do not share it with anyone other than your doctor or other Medicare-approved health care providers.

• Don't give credit card or financial information to anyone calling saying he or she represents Medicare. Medicare will never call and ask for your bank accounts or credit card numbers.

• Never use another person's Medicare card or allow anyone to use yours.

• Do not allow anyone except your doctor or other Medicare-approved provider to review your medical records or recommend services.

• Never let anyone give you "free" equipment or supplies in exchange for your Medicare number.

• Review your Medicare Summary Notice thoroughly to ensure you received each service listed and all the details are correct.

• Report any suspicions of fraud by calling 1-800-HHS-TIPS or 1-800-MEDICARE.

Ray Hurd is the regional administrator for the Boston office of the Centers for Medicare & Medicaid Services. To learn more about preventing health care fraud visit www.stopmedicarefraud.gov.