4 Genetic Tests Worth Getting — And Why Most Aren't

Most genetic tests don’t change what you would do. That single criterion—does this result alter my clinical management?—separates the small category of genuinely valuable tests from the expanding market of consumer DNA products that generate data without generating decisions.

The Framework: Deterministic vs. Probabilistic

Peter Attia’s Episode #392 builds the case around a foundational distinction that consumer genetic testing consistently obscures: the difference between deterministic variants and probabilistic associations. Deterministic variants nearly guarantee an outcome—carry the gene and the condition follows. Probabilistic associations shift odds without deciding fate. Most disease-relevant genetic variants, including those underlying diabetes, cardiovascular disease, and general cancer risk, are probabilistic. Most consumer DTC tests are selling probabilistic associations dressed up as predictive certainty.

This matters because the appropriate clinical response to a deterministic finding (preventive surgery, enhanced screening, cascade family testing) is categorically different from the appropriate response to a probabilistic association (lifestyle modification that you likely should have been doing anyway). Conflating the two leads to either paralysis or false security.

The Four Tests With Real Clinical Leverage

BRCA1/BRCA2: Lifetime breast cancer risk in confirmed BRCA1 or BRCA2 carriers approaches 80% depending on the variant. This is high enough that the finding changes clinical management for almost every carrier—typically including prophylactic surgery, enhanced imaging protocols, and cascade testing of first-degree relatives. These are among the clearest examples in medicine where a genetic result determines a materially different treatment pathway.

Lynch Syndrome: Lynch Syndrome mutations carry near-certain risk of colorectal cancer, along with elevated risk for endometrial, ovarian, and other cancers. Confirmed carriers move to accelerated colonoscopy schedules (typically every one to two years rather than every ten) and gynecologic surveillance. Cascade screening within families is both medically indicated and frequently life-saving.

Lp(a) — Lipoprotein(a): Attia describes Lp(a) as “the most notable hereditary risk factor for cardiovascular health” and characterizes knowing it as “non-negotiable” for anyone with a family history of premature atherosclerotic disease. Lp(a) affects approximately 10–20% of the population. Most of those people are unaware, because Lp(a) is not included in standard lipid panels. Critically, Lp(a) is measured directly from blood—not inferred from a DNA test—and new cardiovascular guidelines recommend at least one Lp(a) measurement for all patients. This is a case where measuring the phenotype directly is more actionable than inferring risk from genetics.

APOE genotyping: Carriers of one APOE4 allele carry two to four times the Alzheimer’s risk of non-carriers. Homozygous APOE4 carriers (two copies) face up to twelve times the risk. This finding informs a specific protocol: aggressive LDL-C management, Mediterranean dietary pattern, sustained aerobic exercise, and more frequent neurocognitive assessment. The result does not guarantee Alzheimer’s, but it changes what a rigorous preventive approach looks like. For more on cognitive biomarker testing as part of a broader longevity panel, see the Alzheimer’s blood biomarker analysis.

Where Testing Doesn’t Deliver

Genetically informed diets are the clearest example of a DTC category that does not deliver clinical value commensurate with its cost. Attia’s stated position: testing each dietary approach for yourself provides a faster, cheaper, and more accurate answer than any genetic panel. Polygenic risk scores for common diseases—combined scores across hundreds of variants—also rarely change management beyond what a thorough family history already indicates.

The question to ask before any test: if this result comes back positive, what would I do differently? If the answer is “nothing specific,” the test is not worth taking at this time.

All decisions about genetic testing and health monitoring should involve a qualified healthcare provider who can interpret results in the context of individual history and risk factors.

Source: Peter Attia

Content created with AI assistance and reviewed for accuracy.