The line between helpful health screening and unnecessary testing has blurred as medical technology advances and direct-to-consumer tests proliferate. While some screenings save lives, experts warn that overscreening can lead to harm, anxiety, and wasted resources.
What Is Medical Screening?
Screening tests look for medical conditions before symptoms appear. The best screenings detect treatable conditions early enough to prevent disability or death without causing harm themselves. Examples include blood sugar tests for diabetes and blood pressure checks for hypertension. These conditions often have long asymptomatic periods, damaging blood vessels in the eyes, kidneys, brain, and heart for years before symptoms emerge. Early detection allows for lifestyle changes and medications that safely prevent progression.
Is More Screening Better?
Not necessarily. Overscreening refers to excessive testing that finds untreatable conditions, insignificant abnormalities, or raises more questions than answers. This prompts costly follow-ups and interventions with unclear benefits.
Full-body MRI scans exemplify the problem. Popularized by celebrities and sold by for-profit companies, they aim to detect silent killers like aneurysms and tumors. However, MRI technology often finds incidentalomas—tiny cysts, nodules, or anatomical quirks of uncertain significance. A review of whole-body MRI studies found that 95% of participants had abnormal findings, about a third required further investigation, and fewer than 0.5% were suspicious for cancer. “Humans are full of abnormality, particularly as they age,” says Gilbert Welch, a researcher of overdiagnosis at Brigham and Women’s Hospital in Boston.
What Are the Harms of Overscreening?
Incidentalomas rarely cause harm but trigger cascades of additional tests, biopsies, and specialist visits—costing time, money, and causing discomfort or complications. Even established tests can be overused. For mammography, long-term data show that more frequent screening substantially increases breast cancer diagnoses, especially early-stage disease, but leads to smaller reductions in advanced cancer and uncertain effects on overall mortality. For older patients, frequent screening may increase unnecessary invasive procedures.
Overscreening also creates worry. Suzanne O’Sullivan, a neurologist at London’s National Hospital for Neurology and Neurosurgery, notes that before a screening MRI, a person may feel healthy—but after an uncertain finding, “I won’t feel healthy any longer.”
For those with specific family or medical histories, earlier and more frequent tests are recommended. For example, experts advise earlier colonoscopies for people with a close relative with colorectal cancer.
What Should You Do Before Getting a Trending Screening Test?
Primary care clinicians can guide evidence-based screening decisions. The FDA does not review all direct-to-consumer tests, and independent evaluations are scarce. Before purchasing a test, ask: Does this test reduce deaths or disability, or just increase diagnoses? How often does it produce false positives or overdiagnosis? Is treatment for findings safer than leaving them alone?
Ultimately, Welch advises focusing on foundational health: “Eat your fruits and vegetables, go play outside,” and find meaningful activity and connection. “We’re teaching the next generation the path to health is by collecting data on yourself,” he says, but “you can’t test yourself to health.”
