This article is an addendum to our previously published series on Longevity & Aging. If you are interested in catching up on our previous articles on this subject, you can click here to be directed to the series intro.
A blood draw has become a wellness status symbol. People now buy panels of 100+ markers, “biological age” scores, glucose sensors for healthy arms, and even a single blood test that claims to screen for 50 cancers. Some of this is the most useful preventive medicine in years. Some of it is a horoscope with a lab logo on it.
Here’s how to tell them apart.
Myth 1: “My cholesterol panel already tells me my heart risk”
Your panel might not be the whole story, and the 2026 guidelines now say so. The updated ACC/AHA dyslipidemia guideline gives its strongest (Class 1) recommendation to measuring Lp(a) at least once in all adults. Lp(a) is a cholesterol-carrying particle that is largely determined by genetics and not significantly affected by lifestyle changes, which is why it’s a once-in-a-lifetime test. About 1 in 5 people worldwide have elevated Lp(a), and a standard lipid panel doesn’t show it.
ApoB testing is more nuanced. It counts atherogenic particles rather than the cholesterol they carry, but the guideline’s endorsement is targeted: it’s considered reasonable in adults on lipid-lowering therapy, particularly those with ASCVD, CKM syndrome, type 2 diabetes, or elevated triglycerides, to guide intensifying treatment. That is not “everyone should track ApoB monthly.”
What a high result means: a high Lp(a) isn’t a death sentence. It’s a reason for more aggressive management of the risk factors you can change, like LDL, blood pressure, and smoking. Drugs aimed specifically at Lp(a) are still being tested in outcome trials.
Verdict: Lp(a) once is worth it. ApoB is worth it for specific groups.
Myth 2: “A ‘biological age’ test shows how fast I’m aging”
These tests measure DNA methylation, which correlates with chronological age, disease risk, or mortality. Critics describe them as correlations to correlations, not direct measures of biological age.
The reliability problem is documented. An analysis of public intervention datasets found that in 5 of 6 datasets, a single clock reported a significant change, and in every case it was a first-generation clock. The authors concluded that some clock changes are likely technical noise and false positives. Results that don’t replicate across clocks are a red flag for any “my protocol reversed my age by 3 years” claim.
One person who bought seven different biological age tests on the same day got a 13.1-year spread in results. That’s a company-run n=1, so treat it as an anecdote, not a study. But it matches the published concerns, and an AMA Journal of Ethics commentary questions the empirical validity of biological age testing and asks companies to be more transparent about reliability.
Verdict: Skip it for now. It’s entertainment, not medicine.
Myth 3: “Glucose spikes are dangerous, so everyone should wear a CGM”
Continuous glucose monitors are transformative for people with diabetes. For everyone else, a 2026 narrative review prepared for JAMA Internal Medicine found no scientific evidence that the technology improves health or prevents disease in healthy people. The lead researcher also warned that CGMs generate enormous amounts of data that are difficult to interpret, and that healthy people are already seeking medical care to make sense of their readings.
There’s a technical catch too: the A1c estimate some CGMs display may overestimate actual A1c in people without diabetes.
Verdict: A legitimate tool if you have diabetes. For everyone else, curiosity with an unproven payoff.
Myth 4: “One blood test can now catch 50 cancers early”
This is the biggest story of 2026, and the real result is more complicated than the headlines.
The NHS-Galleri trial randomized 142,250 participants 1:1 to multicancer early detection testing plus usual care or usual care alone. In the NEJM paper published September 22, the investigators reported that they did not observe a lower incidence of stage III or IV cancers across 12 prespecified cancers, so the trial missed its primary endpoint. A key secondary signal for stage IV cancers had a rate ratio of 0.86, which is suggestive, not conclusive.
The test’s performance looks strong on paper, with specificity of 99.55% and a positive predictive value of 52%. In plain terms, about half of positive signals turned out to be cancer. Researchers also note it’s unknown whether all the cancers found would ever become symptomatic, or whether early diagnosis with the test improves survival.
The regulators are split too. On September 23, an FDA advisory panel voted 7 to 2 (with 1 abstention) that benefits outweigh risks, 6 to 4 on effectiveness, and unanimously on safety. The panel’s vote isn’t a decision: the test is available by prescription as a lab-developed test but has not received FDA approval. It’s intended for use alongside recommended screening, not instead of it.
Verdict: Genuinely promising, but not a replacement for your colonoscopy or mammogram. Watch for the Health Canada’s eventual final decision and survival data.
Myth 5: “More biomarkers means better insight”
Some direct-to-consumer panels now bundle 100+ biomarkers for around $190. Cheap data isn’t free, though. Reference ranges are typically set so that about 5% of healthy people fall outside them for any single marker. Run 20 independent markers and the chance that a perfectly healthy person gets at least one flag is roughly 64% (1 − 0.95²⁰). Each flag can trigger repeat tests, anxiety, and sometimes imaging that finds harmless “incidentalomas.”
The rule I’d use: before ordering any test, ask what decision the result would change. If the answer is “nothing,” you’re buying information, not health.
Sources
Primary / peer-reviewed or official:
- Sasieni P, Swanton C, et al. “Effect of Screening with Multicancer Early-Detection Test on Late-Stage Cancer Diagnosis” (NHS-Galleri), N Engl J Med, published online Sept 22, 2026. Trial registration: NCT05611632. Summaries: ASCO Post, HMP Global
- FDA Molecular and Clinical Genetics Panel, Sept 23, 2026: FDA meeting notice; vote coverage: Targeted Oncology
- 2026 ACC/AHA Dyslipidemia Guideline (JACC / Circulation, Mar 13, 2026): summary slides
- “When to Trust Epigenetic Clocks: Avoiding False Positives in Aging Interventions,” PMC11526921
- “Continuous Glucose Monitoring in Type 2 Diabetes and Beyond,” JAMA Intern Med 2026; Patient Page DOI; University of Gothenburg release
- AMA Journal of Ethics, commentary on epigenetic age testing (Nov 2025): PDF
Secondary / context:
- ecancer: ASCO 2026 coverage of NHS-Galleri
- Law Commentary: what the FDA panel vote means
- Lifespan.io: “When Doctors Prescribe Horoscopes”
- Outliyr biological age case study
- Empirical Health Lp(a) page
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