ATLANTA -- You count on your doctor to keep your medical file confidential but that doesn't mean your secrets are safe. Your insurance company may be more than willing to share that information so other insurers can see it.

Credit bureaus, like Equifax, keep track of how well consumers pay their bills, which can have an impact when a person applies for a loan. But another type of bureau can have an impact on consumers' health coverage.

A person's health record contains some of their most private information, including the prescription drugs they take and their medical conditions.

It's all in your doctor's file but did you know that a private company could also be collecting that information along with things like your driving record and even a list of any risky hobbies?

The Medical Information Bureau, or MIB, gathers this data from more than 500 insurance companies and shares it with its members.

"I didn't think there was any organization in this country that kept track of health histories on Americans," said Russ Darbyshire. "To me that's is a violation of my privacy."

He discovered that he had an MIB file after he was turned down for disability insurance. He said MIB listed a neck injury that had healed a long time ago.

Said Darbyshire: "I wanted it off my record cause it was wrong."

Sixteen million Americans have MIB files that include codes for 230 different medical conditions. They help insurance companies measure the risk of applicants.

"It can be very efficient in getting information and expedites the process for people getting insurance," said insurance agent Dave Evans. "That leads to lower costs."

Officials at MIB would not go on camera but told us the company helps insurers "detect and deter fraud." Industry experts say the information saves them millions of dollars, savings they say are passed along to consumers.

Said Evans: "The more information a carrier has, the better. Absent that information, they're going to charge higher rates."

But privacy advocates aren't sold. The Privacy Rights Clearinghouse said most Americans have no idea these files exist.

"It becomes an invasion when you don't know what's going on," said Beth Givens, a spokeswoman for the group. "And information about you is then used to make very important decisions."

So, what do you need to know about MIB?

Experts agree that you should:

• Contact the bureau to see if there is a file on you.
• Check to make sure it is accurate. If it is not, you can ask for a re-investigation.
• Make sure it is up to date.

"Let's say you had a chronic medical condition several years ago but now you're considered cured, then ask your doctor to submit a letter to the MIB and to your insurance agent, stating that while you at one time had a serious condition you now are well," said patient advocate Cynthia Solomon.

If you have ever been turned down for a policy because of your MIB file, you can always try another insurer.

"If you do get declined, don't take that first one as the final answer," said Evans.

Darbyshire said it took him three years and a lawyer to straighten out his MIB file. He said he learned the hard way about being denied coverage.

"I assumed the process was going to be fair and it wasn't," he said.

MIB officials say it only shares information with member insurance companies who pledge to keep it confidential. And the company claims it has a 99.5 percent accuracy rate.