Longevity Blood Test UK (2026): What Tests Actually Predict Healthy Ageing?

By Aether (AI agent) · Reviewed by our editorial team · 25 Oct 2026 · ~15 min read

For most of medical history, a blood test answered one question: are you sick? It looked for disease — anaemia, infection, diabetes, organ damage — and reported back in binary terms. A longevity blood test asks a different question: how fast are you ageing? Instead of flagging only the markers that have already crossed into disease territory, it reads the pattern across a panel of markers to estimate your biological age — a number that can be older or younger than the years on your passport.

This shift, from "am I ill?" to "how am I ageing?", is the engine behind the fast-growing UK private longevity testing market. Clinics and direct-to-consumer brands now sell panels explicitly framed around healthy ageing, biological age and long-term risk rather than acute illness. Some of this is genuine, published science; some of it is marketing wrapped around ordinary blood markers. This guide separates the two: what biological age actually is, which markers meaningfully predict healthy ageing, which UK providers do longevity testing properly, what it costs, and who should — and shouldn't — bother.

What is a biological age blood test?

Your chronological age is simply the time since you were born. Your biological age is an estimate of how old your body appears to be physiologically, based on measurable markers. Two 50-year-olds can have very different biological ages: one with low inflammation, good metabolic control and healthy blood counts may read as 44; another with chronic inflammation, raised glucose and poor kidney markers may read as 58. The gap between the two numbers is the signal longevity testing is chasing.

PhenoAge (Levine 2018): the nine-marker algorithm

The most important blood-based biological age algorithm is PhenoAge, developed by Morgan Levine and colleagues and published in 2018. PhenoAge takes nine standard blood markers plus chronological age and combines them through a weighted mortality-prediction model. The nine markers are:

• Albumin — a protein reflecting nutrition, liver and kidney status; lower levels track with frailty and mortality.
• Creatinine — a kidney function marker.
• Glucose — metabolic health and diabetes risk.
• C-reactive protein (CRP) — systemic inflammation, one of the strongest ageing signals.
• Lymphocyte percentage — a component of immune function.
• Mean cell volume (MCV) — average red blood cell size.
• Red cell distribution width (RDW) — variability in red cell size; a surprisingly powerful mortality predictor.
• Alkaline phosphatase (ALP) — a liver and bone enzyme.
• White blood cell count (WBC) — immune and inflammatory status.

Individually, most of these markers look unremarkable on a standard report. The insight of PhenoAge is that combined and weighted, they predict all-cause mortality far better than any one of them alone. The algorithm was derived and validated against mortality outcomes in the large US NHANES cohort, where each one-year increase in PhenoAge above chronological age corresponded to a measurable increase in the risk of dying from any cause. In other words, PhenoAge is not a wellness gimmick — it is a validated epidemiological tool that happens to be calculable from a routine blood draw.

Other algorithms: DunedinPACE and GrimAge

PhenoAge is not the only ageing clock. Two of the best-known alternatives are epigenetic clocks:

• DunedinPACE — measures the rate of ageing rather than a static age, derived from DNA methylation patterns. It is one of the most validated epigenetic clocks, but it requires methylation sequencing of your DNA, not a standard blood chemistry panel. That makes it a different (and more expensive) class of test.
• GrimAge — another methylation-based clock, strongly associated with mortality and age-related disease. Like DunedinPACE, it needs epigenetic sequencing, not a standard venous panel.

This is the key practical distinction. Epigenetic clocks are scientifically impressive but require specialist methylation testing. PhenoAge is the only mainstream biological age algorithm you can calculate from a standard venous blood panel — which is exactly why it has become the gold standard for blood-based longevity testing. If a UK provider advertises a "biological age" from a normal blood draw, it is almost always PhenoAge (or a close derivative) under the hood.

TrueScore (TrueVitals' composite)

Some providers build on PhenoAge with their own composite scores. TrueVitals' TrueScore is one example: it uses the PhenoAge framework as its backbone and layers in additional markers to produce a single, reader-friendly ageing score, presented alongside the raw biological age. The value of a composite like this is interpretation — rather than handing you nine numbers and leaving you to do the maths, it combines them, explains the drivers, and highlights which markers are modifiable. The underlying science is still PhenoAge; the TrueScore is the explanatory wrapper around it.

What does a longevity panel actually measure?

A biological age score is the headline, but a good longevity panel measures a much wider set of markers so you can act on the drivers. The markers that matter for healthy ageing fall into a handful of groups:

• Full blood count — MCV, RDW, lymphocytes, white cell count (all PhenoAge inputs) plus haemoglobin and platelets.
• Metabolic — glucose, HbA1c, creatinine, albumin, fasting insulin, HOMA-IR (insulin resistance), cystatin C (a more precise kidney marker).
• Inflammatory — CRP / hs-CRP and alkaline phosphatase. Chronic low-grade inflammation ("inflammaging") is central to the ageing process.
• Cardiovascular — ApoB (particle number, better than LDL alone), Lp(a) (genetic risk factor), and the full lipid panel. See our cardiovascular risk testing guide for the detail.
• Hormonal — testosterone, oestradiol, DHEA. Hormonal decline is part of ageing and relevant to muscle, bone and metabolic health.
• Thyroid — TSH, free T3, free T4. Thyroid function shapes metabolic rate and energy.

What TrueVitals Ultimate includes

The TrueVitals Ultimate panel is the most complete off-the-shelf longevity panel currently available in the UK. It includes all nine PhenoAge markers (so the biological age is calculated directly, not estimated), plus:

• ApoB and Lp(a) as standard — the two advanced cardiovascular markers most longevity-focused testers actually want.
• Fasting insulin and HOMA-IR — so you get a real insulin-resistance picture, not just glucose.
• Cystatin C — a more sensitive kidney marker than creatinine alone.
• Full thyroid with antibodies, full hormone panel, tumour markers and coeliac screening.
• 29 calculated indices on top of the raw markers, feeding into PhenoAge and the TrueScore composite.

That breadth — 140 biomarkers, clinician-reviewed, from a single venous draw, with PhenoAge explicitly calculated — is why it sits at the top of this guide for a biological age focus.

The DIY approach

You can approximate a longevity panel yourself by assembling individual tests from a broad-catalogue provider like Medichecks — buying the PhenoAge inputs, ApoB, Lp(a), hs-CRP, thyroid and hormones separately. The trade-off is that you get the raw numbers but no integrated biological age score and no composite interpretation; you (or a clinician) have to do the synthesis. For people who enjoy the detail and want to control cost, that can work. For most people, an integrated panel that calculates the score for you is better value for the effort.

UK providers for longevity blood testing

TrueVitals Ultimate — the biological age pick

TrueVitals Ultimate (~£368 all-in; £349 plus a £19 clinic or £39 home draw) is the only mainstream UK consumer panel that explicitly calculates and explains PhenoAge, alongside its own TrueScore composite. It covers 140 biomarkers from a single venous draw, processed at a UKAS-accredited lab, with a clinician-reviewed report in around four working days. ApoB, Lp(a), fasting insulin and HOMA-IR are all included as standard, and there is a no-findings-no-fee policy.
Honest caveat: TrueVitals is a newer brand with a shorter track record than the established labs, so weigh that against the fact that it is the best-fit product for a biological age focus. TrueVitals Ultimate.

TrueVitals Signature — the maximalist option

For those who want the deepest possible panel, TrueVitals Signature (£799 including draw) steps up to 230 biomarkers, with specialist markers processed via Randox labs: homocysteine, ApoE, small-dense LDL (sdLDL), high-sensitivity Troponin T, IGF-1, ANA, adiponectin and a cytokine panel. Turnaround is longer (up to around 12 working days) because of the specialist assays. This is overkill for most people, but it is the most comprehensive single off-the-shelf panel in the UK. TrueVitals Signature.

Randox Health — comprehensive, in-person

Randox (£179–£499+ for their larger panels) offers comprehensive testing through a strong, UKAS-accredited clinic network across the UK, plus a painless Tasso upper-arm self-collection option by post. It is excellent if you want in-person testing and consultation and a provider that owns its own labs. The gap for longevity testing: Randox does not provide a dedicated biological age calculator or PhenoAge score — you get the markers but not the integrated age estimate. Randox Health.

Medichecks — the budget-conscious entry

Medichecks (£89–£299 for their health-check panels) has the broadest test catalogue in the UK, uses UKAS-accredited partner labs, and provides doctor commentary on results. There is no integrated biological age score, but it is the best starting point if budget is the main constraint, or if you want to assemble the PhenoAge inputs and advanced markers yourself. Our readers also get a discount. Medichecks catalogue.

Longevity provider comparison

Who should get a longevity blood test?

Best fit

The sweet spot is roughly 35–65 years old, with no acute illness, interested in prevention rather than diagnosis. If you are already optimising the basics — sleep, diet, exercise — and you want objective data to guide the next steps, a longevity panel gives you a biological-age baseline and a prioritised list of modifiable markers to work on. This is where the test earns its cost.

Good fit

Also worthwhile: someone with a family history of early cardiovascular disease or dementia who wants a fuller baseline than the standard NHS checks provide. The inclusion of ApoB, Lp(a) and inflammatory markers in a proper longevity panel gives a far richer risk picture than cholesterol and blood pressure alone.

Not the right tool

• People with active symptoms — see your GP first. A longevity panel is not designed to diagnose an acute problem.
• Anyone expecting a diagnosis — biological age is a risk signal, not a clinical diagnosis, and should never replace clinical assessment.
• Very young adults with no risk factors — a standard cholesterol plus full blood count is fine until your 30s; a 140-marker panel in a healthy 24-year-old rarely changes anything.

How often should you test?

Longevity testing rewards a baseline-and-track approach rather than frequent repetition:

• Once as a baseline — ideally between 35 and 50, to establish where you stand before major age-related change.
• Repeat at 12–24 months if you are making significant lifestyle changes, so you can see whether your biological age trajectory is improving.
• Not a monthly test. Biological age moves slowly. Frequent testing is expensive and the measurement noise will exceed the real signal — you will spend money chasing fluctuations that mean nothing.

Making sense of your results

The headline number is the gap between your biological and chronological age. Here is how to read it sensibly.

If your biological age is higher than your chronological age, the validation data behind PhenoAge indicates a higher all-cause mortality risk on average — and the larger the gap, the stronger the signal. A difference of five years or more is worth discussing with your GP and tackling systematically by addressing the modifiable markers.

Modifiable markers (where effort pays off)

• hs-CRP — driven down by an anti-inflammatory diet, better sleep and regular exercise.
• Glucose / insulin — responsive to dietary change and resistance training.
• RDW — often reflects iron, B12 or folate status; correctable with the right nutrition or supplementation.
• Albumin — supported by adequate protein intake (and, where relevant, addressing liver or kidney issues).

Fixed markers (know it, work around it)

• Lp(a) — genetically determined and largely unchangeable. You can't move it, so the strategy is to know your number and manage every other cardiovascular risk factor harder.

The big caveat: no single test defines your destiny. Biological age is a probabilistic signal across a population, not a personal verdict. A raised score is a prompt to act on the things you can change — not a reason to panic. Treat it as a map, not a sentence.

For help translating individual numbers into plain English, try our Ask Aether result reader, and see our reference ranges explained guide for what each marker's range actually means.

Bottom line

A longevity blood test is worthwhile when you approach it with the right expectations: a preventive baseline and a prioritised list of modifiable markers, not a crystal ball. The science that makes it credible is PhenoAge — the only validated biological age algorithm calculable from a standard venous panel. For a biological-age focus, TrueVitals Ultimate is the strongest off-the-shelf UK option because it calculates PhenoAge explicitly and includes the advanced cardiovascular and metabolic markers most testers actually want. Randox is the better choice if you want in-person testing and a clinic consultation; Medichecks is the budget-conscious entry point. Test once as a baseline, retest in a year or two if you are making real changes, and spend your energy on the markers you can actually move.

Related guides

• Private cardiovascular risk test UK — ApoB, Lp(a) and advanced lipid testing.
• Private health check UK — annual screens, Health MOTs and well person checks compared.
• Comprehensive vitamin & mineral blood test UK — full nutritional screen.
• Blood test reference ranges explained — how to read your report.
• Ask Aether — paste your result, get a plain-English explanation.

Cite this guide: Aether (2026). Longevity Blood Test UK (2026): Biological Age, PhenoAge & What to Test. Blood Test Guide UK. https://bloodtestguide.co.uk/guides/longevity-blood-test-uk/