Recovering from medical identity theft can be particularly tricky because federal privacy laws restrict health care providers from sharing records with "unauthorized" parties. If it's determined the person getting treatment in your records really isn't you, health care providers may balk at providing you with those records.

"It's a crazy, mixed-up world," Foley said. "The thief has privacy rights, too."

The move toward electronic medical records could lead to more identity theft by making large-scale thefts of health information easier if providers don't use proper safeguards, some identity theft experts warn.

But it could also make it easier for providers to segregate a thief's information from your own while linking it to your original file, Foley said. That would allow providers to follow federal privacy laws while still maintaining the integrity of your files.

Preventing health care identity theft is all but impossible, because much of your vital information is already in big databases that are outside your control. But you can guard your health insurance card carefully and take steps to contain the damage if you're victimized. The Identity Theft Resource Center and the World Privacy Forum recommend that you:

  • Scrutinize every "explanation of benefits" form. Health insurers send these out after every claim. Check all of yours for office visits, services or equipment deliveries you don't recognize.
  • Ask your insurer for a complete list of benefits annually. If a thief has changed the billing address on your account, you may never see the individual EOB forms. A complete list of claims submitted and paid each year can help you spot problems.
  • Ask for copies of your records from medical providers. The World Privacy Forum recommends making this request after every visit, so you can check for fraud and reconstruct your records afterward if you're ever victimized. The forum has more information here on what to do if your records are withheld.
  • If you're victimized, contact the health care provider's billing department first. Explain that you're a victim of identity theft and that the charges aren't yours. If the billing department is reluctant to help, you may need to appeal to the health care provider directly. Try to find out if the thief used your health insurance information and/or Social Security number. If so, contact, your health insurer and consider putting a fraud alert or a freeze on your credit bureau files.
  • File a police report. You were the victim of a crime, and filing a police report is often essential in helping you clear your name.
  • Disseminate the information. Send copies of the police report, an affidavit of fraud (.pdf file) and any additional supporting documents to your provider's medical billing department, and to collection agencies and your insurer, if they are involved.
  • Keep the evidence. Hang on to copies of all your paperwork and ask the provider to provide a "letter of clearance" acknowledging you were the victim of identity theft. This paperwork can help short-circuit problems that could crop up later if, for example, the phony bills arise as collection accounts.

Liz Weston is the Web's most-read personal-finance writer. She is the author of several books, most recently "The 10 Commandments of Money: Survive and Thrive in the New Economy" (find it on Bing). Weston's award-winning columns appear every Monday and Thursday, exclusively on MSN Money. Join the conversation and send in your financial questions on Liz Weston's Facebook fan page.