# The biomarkers longevity clinics track

Source: https://www.longevityehr.com/biomarkers

What each marker measures, what current guidelines say, and how to follow it over time. Written for clinicians and clinic operators.

## Browse the library

- [Optimal vs reference ranges](https://www.longevityehr.com/biomarkers/optimal-ranges): Why longevity clinics set their own ranges, and how to do it carefully.
- [ApoB](https://www.longevityehr.com/biomarkers/apob): Apolipoprotein B and cardiovascular risk.
- [Lipoprotein(a)](https://www.longevityehr.com/biomarkers/lipoprotein-a): The inherited cardiovascular risk marker.
- [HOMA-IR](https://www.longevityehr.com/biomarkers/homa-ir): Estimating insulin resistance from fasting glucose and insulin.
- [Fasting insulin](https://www.longevityehr.com/biomarkers/fasting-insulin): An early signal of metabolic dysfunction.
- [hs-CRP](https://www.longevityehr.com/biomarkers/hs-crp): Low-grade inflammation and cardiovascular risk.
- [Vitamin D](https://www.longevityehr.com/biomarkers/vitamin-d): 25-hydroxyvitamin D testing and what the guidelines say.
- [Ferritin](https://www.longevityehr.com/biomarkers/ferritin): Iron stores, deficiency and overload.