NEW YORK (CNNMoney.com) - Julie Hernandez had no idea she was a convicted shoplifter.

Then, three days before she was supposed to start a new job as an executive assistant at a Fortune 500 food company, Hernandez got a call from her employer-to-be.

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"They advised me they were not going to move forward with the hiring process due to the result of a background check," said the 38-year-old Chicago-area resident. "I was like 'what is this?'"

So Hernandez got a hold of the company that did the check, got the case number of the crime she had supposedly committed and went to the county court.

Sure enough, Hernandez said the woman on the case number had a different name, different birthday, different social security number. She says she's fallen victim to one of the fastest growing areas personal information trouble -- mistaken identity.

"We're getting an increasing amount of questions about background checks, almost as many as identity fraud," said Tena Friery, research director for Privacy Rights Clearinghouse, a California-based consumer education organization. "There are too many problems with inaccurate information being recorded."

The ratio of mistakes doesn't appear to be particularly high. ChoicePoint, a company that performs background checks, says of all the checks it performs only about one in a thousand are disputed by the subject.

Still, Friery pointed to the serious repercussions of having a bankruptcy or criminal record attached to your file, and said "If you happen to be the person on the wrong end of that number, it can be devastating."

And that number is bound to grow as digital records have brought down the cost of performing background checks and the number of companies conducting them and Internet sites providing them proliferate.

According to the Society for Human Resource Management, 51 percent of its members performed back ground checks on at least some of their prospective hires in 1996. By 2004 that number reached 80 percent.

So what can you do to protect yourself?

Friery said under federal law any company that performs a background check must provide the subject with a free copy of the results upon request.

The problem, she said, is that sometimes employers don't tell their prospective employees what company is performing the check. In addition, employers don't need to tell a prospective hire that they didn't get the job due to information on the check, they could simply say there was a more qualified candidate.

The Privacy Rights Center is working to make it mandatory that employers must tell people who performed the background check. In the meantime, she said to insist on getting the name of the company before you sign an agreement to have a check run on you.

Friery said to monitor your credit by utilizing the free annual credit reports that the big three agencies -- Experian, Equifax and TransUnion -- must now provide under law.

Also, if you know you have a black mark or two on your record, Friery said to go to the court where the records are kept and make sure the charges are what you think they are. She said all too often people think a case had been filed or dismissed then, due to a clerical error, it's filed as something else.

Jason Morris, co-chairman of the National Association of Professional Background Screeners, said any reputable background company would tell their clients to pass along its name to employees and also have clear, easy procedures in place for people to dispute information.

But he admits that problems could arise.

"The process in place is very solid," he said. "But some companies don't follow it."

As for Hernandez, she's been unemployed for the past two months, unwilling to apply for another job and have the same thing happen again while trying to find a lawyer to help clear her name.

"But all the attorneys require a fee, and obviously I'm not working," she said. "So I'm stuck."

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