# PhenoAge (PhenoAge)

Nine routine markers combined into an age-like number calibrated against ten-year survival in a US population (Levine 2018); a research index.

Type: index · Unit: years · Domain: Metabolic Health · Accuracy: Calculated · Importance: Context

Also called: phenotypic age, biological age from blood, blood age, Levine age, PhenoAge acceleration

## In one sentence

Nine routine blood results and your age combined into a single age-like number, calibrated so that it reads as the age at which a US population would have had the same ten-year survival; it is a research index, shown with a research label, and it moves when inflammation, kidney, liver and glucose markers move together.

## Why it matters

The index was built in two steps. From 42 clinical markers measured in the US NHANES III survey, nine were selected with age and fitted to mortality over the following years, and the result, Phenotypic Age, was then used as the target for an epigenetic clock, DNAm PhenoAge, which outperformed earlier clocks for all-cause mortality, cancers, physical functioning and other outcomes (Levine 2018). The clinical version was then tested on its own in an independent sample of 11,432 US adults aged 20 to 84 followed for 12.6 years: after adjusting for chronological age and sex it was associated with all-cause and most cause-specific mortality, the association held in seemingly healthy people and in every stratum of age, ethnicity, education and health behavior, and people with more diagnosed conditions read older, by about 0.6 years with two or three conditions among young adults (Liu 2018). What it adds for a member is a way to see nine markers move as one; what it does not add is a statement about any one person's future, which is why VT labels it research and never prints it on a clinician card.

## What moves it

The inputs: albumin (lower reads older), creatinine (higher reads older, which is where creatine and muscle mass mislead it), fasting glucose, CRP (on a log scale, so an infection moves it a lot), lymphocyte percentage, mean cell volume, red cell distribution width, alkaline phosphatase and white cell count, with chronological age carrying most of the weight. A cold in the week before the draw, a hard session the day before, dehydration and a creatine habit each move it by years without anything about aging having changed, which is why the pre-draw rules are the price of a meaningful value.

## How to measure it well

It needs the core panel from one draw taken under the panel's rules: fasting, morning, rested, well for two weeks, no hard training for 48 hours. A standard CRP reported as "<5" cannot feed the log term, so the index needs high-sensitivity CRP. Compare values only between draws taken the same way.

## How Vitality Tracker uses it

Computed only when every input comes from one collection (the same-draw rule), shown on the labs dashboard with the research label and the gap between it and your age (PhenoAge acceleration), and never on a clinician card or in the Vitality Score. When the Supplement Tracker holds creatine, the creatinine term is flagged and the value is read as a within-person trend only. There is no working optimal: the index is read against your own earlier draws, with the note that a one- to two-year move between two draws is within the noise of its inputs.

## How far to trust the number

Calculated: every input error passes through, and the log CRP and creatinine terms pass through most. Treat whole years as the resolution and a change of less than two years as nothing; the association in the cohorts is a population finding, not a measurement of any one person's aging.

## Method

A linear score is formed from the ten inputs with the published coefficients (Levine 2018, supplementary table; Liu 2018): albumin in g/L, creatinine in µmol/L, glucose in mmol/L, the natural log of CRP in mg/dL, lymphocytes as a percentage of white cells, MCV in fL, RDW in percent, alkaline phosphatase in U/L, white cells in ×10⁹/L, and age in years. The score is converted to a ten-year mortality probability by a Gompertz survival function, and that probability back to the age at which the reference population carried the same probability. VT uses the coefficients from the paper's table; units are converted from the laboratory's to the formula's by the lab catalogue's factors.

## Sources

1. Levine ME, et al. An epigenetic biomarker of aging for lifespan and healthspan. Aging (Albany NY) 2018;10:573–91. [doi:10.18632/aging.101414](https://doi.org/10.18632/aging.101414)
2. Liu Z, Kuo PL, Horvath S, Crimmins E, Ferrucci L, Levine M. A new aging measure captures morbidity and mortality risk across diverse subpopulations from NHANES IV: a cohort study. PLoS Med 2018;15:e1002718. [doi:10.1371/journal.pmed.1002718](https://doi.org/10.1371/journal.pmed.1002718)
3. Vitality Tracker, Recommended baseline lab panel v0.1; Clinician report content specification.

## Related

- [Full blood count with differential](https://vitalitytracker.app/knowledge/full-blood-count)
- [CRP, high-sensitivity](https://vitalitytracker.app/knowledge/c-reactive-protein)
- [Liver function](https://vitalitytracker.app/knowledge/liver-function)
- [Renal function and electrolytes](https://vitalitytracker.app/knowledge/renal-function-and-electrolytes)
- [Fasting glucose](https://vitalitytracker.app/knowledge/fasting-glucose)
- [Metabolic age](https://vitalitytracker.app/knowledge/metabolic-age)
- [Getting your blood tests done in New Zealand](https://vitalitytracker.app/knowledge/blood-tests-in-new-zealand)

Reviewed October 2026 · v1

Source: https://vitalitytracker.app/knowledge/phenoage