Commercial Composite Scores

What a composite score is

A commercial composite score takes many measurements, such as blood markers, DNA methylation or wearable data, and combines them with a formula into one number: a "health score", "biological age", "longevity score" or "inflammation index". The formula is often proprietary, meaning the company does not publish how markers are weighted. A single number is easy to read, which is exactly why it needs checking. Evidence labels used: established, promising but limited, insufficient evidence, marketing claim.

Claim check

1. "Our score measures your true biological age"

   In one analysis, technical noise produced up to 9 years' difference between replicate samples for six epigenetic clocks [1]

   What to ask: Is the measurement repeatable?

2. "Our score predicts your risk"

   A protein-based score added only a small improvement (C index change 0.014) over clinical risk factors in an Iceland analysis [2]

   What to ask: Predicts what outcome, in whom, beyond standard measures?

3. "Improve your score and improve your health"

   Reviewers say many widely marketed biomarkers lack evidence of clinical utility [3]

   What to ask: Was improving the score tested in a trial with health outcomes?

4. "FDA registered / compliant"

   See the regulation section below

   What to ask: Registered or approved for what exact claim?

Three levels of proof

Reviewers describe three thresholds that a biomarker must meet for preventive use: analytical validity, clinical validity and clinical utility, and only a minority of biomarkers currently meet them. [3]

1. Analytical validity: the number is measured reliably.
2. Clinical validity: the number is linked to a disease or outcome in people like you.
3. Clinical utility: using the number improves health outcomes compared with not using it.

Many products emphasize the first, imply the second, and say little about the third. We searched PubMed for randomized trials showing that a commercial composite score improved health outcomes and found none; this is a search result and not proof that none exists. Until one is shown for a specific product, improvement claims are a marketing claim.

Four common pitfalls

• Hidden weights. If you cannot see how markers are combined, you cannot judge whether one marker is driving the score.
• A moving target. Two samples from the same person can give different results because of measurement noise. [1]
• Reference group. A score compared with "your age group" depends on who is in that group.
• Biomarker is not outcome. A score going down is not the same as living longer or avoiding disease. See biomarker changes vs meaningful health outcomes.

Downsides of testing healthy people

Unvalidated results can cause overdiagnosis, false positives, psychological distress and diagnostic cascades, and are often misinterpreted by patients. [3] See multiple testing and overdiagnosis.

How to use a score safely

Treat any composite score as a conversation starter, not a diagnosis. Bring it to a clinician, ask which single measurements drive it, and do not start supplements, stop medicines or buy further tests only because of the number. Related reading: biomarkers and biological age tests, direct-to-consumer epigenetic age tests, home lab testing and longevity clinic panels, and talking with a health professional.