Over-testing, honestly — the tests you probably don’t need

The longevity market sells testing as caring for yourself: more scans, more biomarkers, more numbers. The honest headline: for people without symptoms or risk factors, more testing does not mean more health — and it carries real harm through false positives, incidental findings and cascades of follow-up. A test is worth doing when it answers a specific question and could change what you do. The most useful stance is not “test everything”, it is “test on purpose, with your doctor”.

Why more testing is not more health

It feels obvious that checking more must be safer. But a test is not information for free — every test has a false-positive rate, and run enough tests on a healthy person and some will come back abnormal by chance alone. Each abnormal result then triggers more tests, scans, biopsies, cost, waiting and anxiety — often to confirm that nothing was ever wrong.

This is why medical societies now publish lists of tests to avoid, not just tests to do. The Swiss "smarter medicine" campaign (the Choosing Wisely arm) exists precisely to counter the reflex that more is better — and one of its headline recommendations is not to do routine, comprehensive check-ups in people without symptoms.

What the evidence actually shows

This overturns the "annual full check-up" instinct.

• Routine general health checks don’t make healthy adults live longer — A large Cochrane review of randomized trials found that general health checks in asymptomatic adults do not reduce overall, cardiovascular or cancer mortality. Screening healthy people top-to-bottom "just in case" mostly generates diagnoses and treatment without extending or improving life. Targeted, evidence-based screening is a different thing (see below). (established)
• Swiss GPs explicitly advise against routine check-ups and some routine tests — The SGAIM/"smarter medicine" Top-5 list for ambulatory general internal medicine recommends against regular comprehensive health check-ups in asymptomatic people and against routine vitamin D testing in people without risk factors — among the most over-ordered tests in practice. (established)
• Whole-body scans mostly find harmless "incidentalomas" — Direct-to-consumer full-body MRI and CT scans find incidental spots in a large share of healthy people — the great majority benign. Each one can start a cascade of follow-up imaging, specialist visits and biopsies, with their own risks (and CT adds radiation), to rule out a problem that was never there. Reassurance is not what they reliably deliver. (established)
• Even "real" screening has a downside: overdiagnosis — Some cancers found by screening would never have caused harm in a person’s lifetime, but once found are treated anyway. PSA screening for prostate cancer is the classic example: a small possible mortality benefit against substantial overdiagnosis and overtreatment — which is why guidelines call for an individual, informed decision, not automatic testing. (established)

The harms people underestimate

• False positives and anxiety are the common harm — The most frequent harm of over-testing is not radiation — it is a scary abnormal result in a healthy person that turns out to be nothing, after weeks of worry and further tests. This is real harm, even when the ending is happy. (note)
• Cascades: one test orders the next — An incidental finding rarely ends the story; it starts a chain of confirmatory tests, referrals and sometimes procedures, each with its own small risk. The initial "harmless" scan can end in an invasive biopsy. (note)
• A number without a plan doesn’t help — Tracking dozens of biomarkers with no question and no threshold for action mostly produces noise and worry. If a result would not change anything you or your doctor do, testing for it rarely helps. (note)

When testing genuinely earns its place

This is not "never test" — it is "test on purpose".

• You have symptoms or specific risk factors — Testing driven by a real question — a symptom, a strong family history, a known risk factor — is where diagnostics do their job. The argument here is against blanket testing of the well, not against investigating a genuine concern. (established)
• Evidence-based screening programmes for the right age group — A handful of screenings clearly save lives when applied to the recommended population: colorectal cancer screening, cervical screening, and blood pressure among them. These are targeted, evidence-tested and time-bounded — the opposite of an unfocused full-body scan. (established)
• The five questions before any test — Choosing Wisely’s patient questions are the practical filter: Do I really need this test? What are the risks? Are there simpler, safer options? What happens if I do nothing? And what does it cost? A test that survives those questions is usually worth doing. (note)

What we still don’t know

• Whether "personalised" risk-based screening beats standard programmes Tailoring who gets screened, and how often, by individual risk is promising but not yet proven to beat the established age-based programmes for most conditions.
• Where the line sits for some newer tests Multi-cancer early-detection blood tests and routine advanced imaging are marketed hard, but whether they help more than they harm in healthy people is genuinely unsettled — which is exactly why caution, not enthusiasm, is the evidence-based default for now.

The practical takeaways

Be sceptical of "executive health" packages, direct-to-consumer full-body scans and large biomarker panels sold as prevention — for people without symptoms they mostly find things to worry about, not years to live. Do keep up with the evidence-based screenings recommended for your age and risk, and investigate real symptoms promptly.

Before any test, ask the one question that cuts through the marketing: "Will the result actually change what we do?" If yes, test. If no, the test is unlikely to help — and decide it together with a doctor who knows your situation, not a company selling the scan.

Key terms

• Over-testing Ordering tests without a specific question, especially in people without symptoms; generates false positives and cascades without improving health.
• Incidentaloma An incidental finding on a scan — usually harmless — that triggers further tests to rule out a problem that was never there.
• False positive An abnormal test result in someone who does not have the disease; the most common harm of over-testing.
• Overdiagnosis Detecting a real condition (e.g. a cancer) that would never have caused harm in the person’s lifetime, leading to needless treatment.
• Cascade The chain of follow-up tests, referrals and procedures set off by one abnormal or incidental result.
• Choosing Wisely / smarter medicine Clinician-led campaigns identifying low-value tests and treatments to avoid; "smarter medicine" is the Swiss arm.