Image: Medical bills © PhotoAlto, Eric Audras, PhotoAlto Agency RF, Getty Images

If you want to keep your credit rating strong, you might want to stay away from a hospital or other medical facility. Even if you have good insurance or can pay for any illnesses or emergencies that arise, you could wind up with a collection account on your credit reports, and your credit score could tank as a result.

Some 30 million Americans were contacted by collection agencies in 2010 regarding unpaid medical bills, according to research by the Commonwealth Fund. And previous research from the Federal Reserve found that more than half of all collection accounts on credit reports are related to medical bills.

Here are four common misconceptions about medical bills that can cost you dearly:

Myth No. 1: As long as I am making payments on a medical bill, it can't be sent to collections.

The truth: Making payments on a medical bill doesn't necessarily keep it out of collections. If you are making small payments, or if you make your payment a few days late when you are under a payment arrangement, you may discover the provider has turned over the bill to collections.

And consumer protections are few and far between. In California, hospitals are required to give patients a 150-day period during which they can negotiate their hospital payments before their medical bills are sent to collection agencies, according to Families USA. And in Minnesota, the group says, there is a clear process for "patients to dispute or challenge bills from hospitals or clinics, and no judgments may be made against patients until they are given a fair chance to respond." But for the most part, any unpaid balance is fair game.

Myth No. 2: I have to be notified before a medical bill is turned over for collections.

The truth: You may not even know you have an unpaid medical bill until you get a call or letter from a collection agency. At that point, it may be too late to avoid damage to your credit. Bills fall through the cracks, are sent to the wrong address or sometimes are not sent to the patient before they are turned over to collections. And when that happens, tough luck.

While some collection agencies will agree not to report medical collection accounts that are paid off immediately, others refuse to do so. And some bill collectors will use the threat of credit report damage to try to get patients to pay up, even if the bill itself is disputed.

Myth No. 3: Medical collection accounts are treated differently than other types of collection accounts when credit scores are calculated.

The truth: Medical providers, such as doctors and hospitals, don't typically report medical bills. In fact, these bills generally don't show up on credit reports unless they are sent to collection agencies, which often do report them. And at that point, there is no distinction between medical collections and other collection accounts. "When a medical debt is outsourced to a third-party collection agency, it is treated the same as other debts that are in collection," says Jeff Richardson, the vice president of public relations for VantageScore Solutions.

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FICO's policy is similar: It does not distinguish between medical and nonmedical collection accounts when calculating credit scores. In an Associated Press article, a FICO representative noted that a single collection account could cause a 780 FICO score to drop by 105 to 125 points. That's enough to bump someone from a "prime" score to an "off-prime" or even "subprime" score.

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