Lay opinion vs evidence: APOE Check

The APOE genetic test is often marketed as an 'Alzheimer's test,' but the reality is more nuanced. The ε4 allele is the strongest known genetic risk factor for late-onset Alzheimer's disease (odds ratio ~3–4 for one copy, ~10–15 for two copies). However, many ε4 carriers never develop dementia, and many non-carriers do. The predictive power for an individual is low – the test does not predict timing or severity. Lay opinion: 'A positive result means Alzheimer's.' Evidence: It means increased risk, not destiny. Moreover, no proven prevention strategies exist for carriers; guidelines generally advise against testing asymptomatic individuals. Direct-to-consumer tests often overstate the implications. The test can be useful in a genetic counseling context, but as a standalone 'longevity check' it is misleading.