Savvy consumers know to check their credit score before applying for a loan. What is less well known is that consumers can improve their chances of getting insured -- and of paying lower premiums -- by checking that medical information held by doctors, hospitals and pharmacies is accurate.

Errors in medical records aren't uncommon. "They happen all the time," says Joy Pritts, research associate professor at Georgetown University's Health Policy Institute.

Mistakes can arise from a mistyped diagnosis code or transcription error to an inaccurate diagnosis or a diagnosis that is out-of-date, say because a patient has gotten his or her cholesterol under control. And, if you have a common name, other peoples' records can end up in your file, says Ms. Pritts. Part of the problem is that the U.S. health-care system relies mainly on paper records, which make it harder to coordinate care and spot errors.

Even if your medical records are complete – and completely accurate – there is stuff in there that an insurance underwriter will zero in on to assign you to a higher risk pool – which could mean that your monthly premium could be higher than your mortgage or rent – even if you are in good health. Consider this scenario:

A 35-year old divorced woman is going over the results of her lab tests with her doctor. The patient has two tween-age children, and took her widowed mother into her home two years earlier after a stroke left her unable to live on her own – though still able to walk, dress and bathe herself

The patient is a non-smoker and within 10 pounds of a weight her doctor considers optimal. However, her blood pressure is borderline and her cholesterol is a bit high. The doctor tells her that both conditions can be managed without medication, if she exercises at a moderate level of intensity for 30 to 45 minutes a day.

She looks at the doctor incredulously, and launches into a plaintive protest:

"Are you kidding me? Do you know what my life is like? I have a 45-minute drive each way to work, and that’s after I drop the kids off at school and leave my mother at a daycare program for seniors. I’m lucky that my neighbor brings the kids home from school, but I have to leave work at the crack of 5:00 to fetch my mother. If a late afternoon meeting is running long, I’m eating my heart out thinking I’m not going to get to the senior center in time. My mother is as independent and healthy as can be expected, but she’s very demanding and critical of everything I do. Not only I have no time to exercise, I feel like I am constantly late for something. My social life has dwindled down to zero – I have no time for my friends, and it’s been ages since I’ve been out on a date. I often feel trapped, which depresses me no end."

If you think this is a private exchange between this patient and her doctor you’re wrong. The doctor has been taking notes the entire time, and the details of this conversation are immortalized in the patient’s medical records.

Should this woman lose her health benefits, because her company can no longer afford to insure it employees or the company goes belly up and she’s out of work, underwriters at all the insurance companies from which she will try to purchase individual coverage will look at the doctor’s notes and conclude she is a high risk.

Despite being a normal weight non-smoker she will be deemed a heart attack waiting to happen, because of her cholesterol and blood pressure readings. Her reference to depression will also be flagged as a potential suicide. Every health insurance company she contacts will offer her coverage – as they are required to under HIPPA – but they will want to charge more than $1,000 a month just for her, never mind the kids. (The American Sleep Apnea Association Web site has a great explanation of why people get "rated" and how underwriters determine how much to charge you for health care coverage.)