"I met with the office manager, the supervisor I would have worked with," said Matthews, 27, a single mother who lives in Newark, N.J. "They loved me."

And, in fact, she was offered the job. But then Johnson & Johnson ran additional background checks and came up with information on her credit report the company found unsatisfactory.

"Just a few hours later, they wanted to take the offer back," Matthews said. "I told them, I've already told my employer I was leaving. I felt they were playing with my life."

Credit reports have long been used to determine whether consumers can get credit cards and mortgages, and the rate they'll have to pay on them. But these reports — and credit scores generated from them — are increasingly being applied to other things, from setting the price on auto insurance to analyzing prospective tenants and screening job applicants.

Consumer activists argue that the system is unfair to many Americans, especially those with little credit experience or with blemished credit records. And some people have begun fighting back in the courts.

"The reality is there are many permissible reasons for organizations to pull your credit report," said Evan Hendricks, a privacy expert who wrote "Credit Scores & Credit Reports: How the System Really Works, What You Can Do." "At the same time, it's confusing, shrouded in mystery and constantly changing — and that works against consumers."

Credit reports are the records kept by credit agencies — including Experian, Equifax and TransUnion — that track the amount of credit consumers have and whether they pay their bills on time. Scores can be derived from the credit reports, either by the agencies themselves or private companies that are customers, to reflect an individual's creditworthiness. The best known is a FICO score, used since the 1990s by banks and other lenders when they underwrite home mortgages.

One of the most contentious uses of credit reports is in employment.

Matthews has filed a complaint with the Equal Employment Opportunity Commission, charging racial discrimination. Matthews is black.

Attorney Adam Klein, a partner at Outten & Golden in New York who is representing Matthews, said the case maintains that a person's creditworthiness "has nothing to do with employment suitability." He also argued that the linkage may be especially damaging to minorities — who are more likely than whites to be denied credit in the first place — as well as women and recent immigrants.

Johnson & Johnson said in a statement that its background checks enable the company to "identify the existence of negative credit-payment history, such as delinquency and default." It added, "a negative credit-payment history may impact a job offer where the history identifies issues significant to the position involved."

The company also said it apologized to Matthews for "the mistaken communication" about the job.

The use of credit scoring in the insurance industry also is being challenged.

Many companies generate their own "custom scores" to set premiums on homeowners and auto insurance.