A composite index turns a panel of biomarkers into one score. Biomarkers are grouped into domains, each domain gets a score, and the domain scores are weighted and added up.
| Index | Name | Domains | Biomarkers |
|---|---|---|---|
| CBMI | Composite Biological Musculoskeletal Index | 5 | 21 |
| CBOAI | Composite Biological OrthoAge Index | 5 | 15 |
| CBNI | Composite Biological Neurofunction Index | 5 | 11 |
| CBLAI | Composite Biological LegAge Index | 7 | 25 |
| CBVAI | Composite Biological Venous Aging Index | 4 | 10 |
How an index is calculated
Z-score each biomarker
The healthy range is read as the middle 95% of healthy values, so:
- Mean is
(L + U) / 2. - SD is
(U − L) / 4. - Z is
(value − mean) / SD.
Only the size of the deviation counts, so each biomarker gives |Z|. See Biomarkers for every range.
Average each domain
Mean |Z|d is the average |Z| of the biomarkers in domain d.
Weight each domain by its share
Wd is the domain's share of the total: Mean |Z|d / Σ Mean |Z|d. The weights add up to 1, so domains that are further out of range count for more.
Apply the domain priority
αd is a fixed priority for each domain, set per index. The same domain can have a different αd in different indices.
Add it up
The domain score is k × αd × (Mean |Z|d × Wd), with k = 1. The index is the sum of the domain scores:
Index = Σ k × αd × (Mean |Z|d × Wd)
Reading a score
- A result inside its healthy range has a |Z| of 2 or less, so a panel with every result in range keeps every domain low.
- The score has no fixed upper limit. It is most useful compared over time for the same person.
- Each index has its own domains and αd values, so scores from different indices are not comparable.
This section is general information, not medical advice.