How can that be? Most adults go to the doctor when they're legitimately ill, and competent physicians use those appointments as opportunities to offer unrelated preventive services. About three-quarters of the people who get an annual checkup have been to the doctor for some better reason in the previous 12 months. Very few preventive health services are required every year, or even every two years. Even if you go years without seeing a doctor — congratulations, by the way — you can get those services (screenings for various diseases or counseling on smoking cessation or weight loss, for instance) without wasting your time at an annual checkup.
Many primary-care doctors order totally unnecessary procedures during annual exams, squandering patients' time and our health care dollars. Perhaps they just want to make patients feel like they're doing something. Here's where this stops being about the efficiency of the health care system and starts being about you: unnecessary screenings can be hazardous to your health.
People have a hard time viewing screenings as dangerous. Take, for example, the "hands off my mammogram" uprising that followed a 2009 government recommendation that mammograms be started later in life and conducted less frequently. Reactions of this kind appear to be based on two misunderstandings. First, many people overestimate the accuracy of screening exams. The false positive rate for a single screening exam is usually low, but when you take them year after year, it becomes very likely that a healthy patient will receive a false positive. A 2009 study showed that, for many cancer screening tests, a patient who undergoes 14 screenings has more than a 50 percent chance of a false positive.
That leads us to the second misunderstanding. Contrary to popular belief, following up on false positives isn't just expensive and anxiety-inducing — it's dangerous.