A couple of weeks back I introduced the Healthy Couch Potato. This is a person who makes decisions about diet, exercise and medical care, sets those in motion, and then forgets about it. One of the key pieces of that concept is a doctor who wants to keep you healthy and won’t make you sicker in the process.

For example, patients can end up sicker in their quest for health by over screening. Screening tests have done a lot to improve the collective health of our nation.  Pap smears and colonoscopies are huge success stories in disease screening. These tests can identify conditions before they become life-threatening and allow patients to stop disease in its tracks.

But, screening tests don’t come without risks. The colonoscopy, which is widely agreed to be a useful test for people aged 50-75, carries a low risk of bowel perforation.  Certain screening tests, such as chest x-rays and mammograms come with radiation exposure. These risks are well-defined and easy to attach a value to.

Another risk, overdiagnosis, is trickier to pin down. Some diseases can go undetected without causing illness or death in the patient. For example, there is concern that mammograms sometimes detect tumors at a stage so early that the body’s immune system might have halted the cancer if left to do its thing. Since there is no way to predict which tumors fall in that category, diagnosis leads to medical interventions – lumpectomies, mastectomies, reconstructions, expensive follow-ups. That is overdiagnosis.

What this means is the Healthy Couch Potato has some decisions to make. At your next doctor's visit, he will list the screening tests your recent birthday makes you eligible for. It’s wise to take some time and research your options. You wouldn’t attend a steak dinner and buy the mutual fund offered over cherries jubilee without a little due diligence would you? You shouldn’t make a snap decision about medical screening either.

The US Preventive Services Task Force (USPSTF) exists to “help primary care clinicians and patients decide together whether a preventive service is right for a patient's needs.” They review tests and give them a grade of A, B, C, or D. Some tests get a grade of “I” which means there isn't enough evidence to recommend for or against the screening test.

The grades offer a useful data point, but remember that these recommendations are based on a benefit or lack of benefit for the population as a whole, not for you as an individual. A prostate specific antigen (PSA) test (which gets a grade of D for the asymptomatic male) might actually reveal a dangerous prostate cancer for you, but the population as a whole doesn’t gain significant benefit from widespread PSA screening.  You might be one of the people who have a mastectomy that in the end would never have been necessary if it weren’t for that mammogram. But you will never know these things, even in hindsight.

This means you have to evaluate the things you can know in light of your own priorities. This is where the real value of the USPSTF comes in for the Healthy Couch Potato. Their summaries of the benefits and harms related to screening are a great resource as you evaluate your choices. They also offer a detailed bibliography of the pertinent research they use to evaluate the tests.

So when it comes time to make some decisions about which screening tests you are going to have and which you will decline, familiarize yourself with this material and have a conversation with your doctor about your own priorities.

This is tricky, but remember, uncertainty does not mean the worst possible outcome is headed your way. The best you can do is to make an educated decision and then cross it off your list. As much as you would like, you can’t predict the future.  So instead of fretting about it, use your time to read a good book, visit an old friend, or climb a new mountain. Worrying won’t change tomorrow, but it sure can ruin today.