Not everyone, however, buys the argument that medical credit checks are beneficial to consumers. For example, consumer advocates worry that the credit checks open an avenue for health care providers to pressure patients into immediate payment.

"The danger, really, is that health care providers, particularly hospitals, may find lines of credit that people have open and really ask people to tap those lines of credit," says Amy Traub, a senior policy analyst at the think tank Demos.

Traub is especially worried that consumers with access to plastic will be pressured into putting their bills on a high-interest credit card, which could make the already high cost of receiving health care multiply. "It's no longer the hospital's problem if you have a credit card bill," she adds. "I think it's important to see that there is a very serious potential downside for consumers."

Credit reporting executives say they haven't heard of that happening. However, at least one provider, TransUnion, said that available credit (meaning, the difference between what you already owe on a credit card and the amount you're allowed to charge) was included in the report. Experian, in turn, said they mostly provide credit scores to health care providers, but didn't disclose what information went into generating those scores.