"In a urinalysis, doctors look for protein or blood in the urine to check for chronic kidney disease," explains Ateev Mehrotra, a doctor who studies health care policy at Harvard Medical School and the RAND Corporation. "If it's positive, you do a repeat. If that's positive, you ultrasound the kidney and then possibly do a biopsy. The risk is low, but kidney biopsy can lead to hemorrhage and even kidney removal."
Kidney biopsies are perfectly reasonable procedures when a patient has symptoms of kidney disease. But looking for disease in an otherwise healthy patient, then performing a series of interventions to prove the screening test wrong — that's bad medicine.
There's also the risk of unnecessarily "medical-izing" minor illness. People who go for annual checkups typically report symptoms that they would have otherwise ignored. In some cases, that's a good thing — some patients minimize their symptoms and ignore the warning signs of serious illness. Most of the time, however, it forces the physician to investigate and treat a problem that would have gone away on its own.
(Optional add end)
There's one largely unmeasurable argument in favor of the annual checkups: They build relationships between doctor and patient, and open lines of communication are important in medicine. That's a valid point, but that benefit has to be weighed against the costs.
"The average bank teller 20 years ago would have argued that the ATM prevents them from building important relationships with their clients, and bank customers would have agreed," notes Mehrotra. "But time is valuable, too, and we shouldn't forget that."
Mehrotra points out that an average patient likely takes two hours off of work for a doctor's appointment. If you multiply that by the average wage and total number of annual checkups in a year, these appointments cost the U.S. economy almost $2 billion in lost productivity alone. Relationship building probably isn't worth that much, especially since you can catch up with your primary-care doctor when you're ill.
In addition, while you're spending time getting to know your doctor, chatting about your hobbies and your grandparents, there are other patients waiting weeks or months for an appointment. And some of them are actually sick.
Palmer is Slate's chief explainer. He also writes How and Why and Ecologic for the Washington Post. Email him at email@example.com.