The blood test your doctor does every year is probably designed to detect disease, not optimise longevity. And there's the problem: by the time obvious abnormalities appear, you've been accumulating silent damage for years.
The difference between reactive medicine and preventive medicine lies in the biomarkers you measure. A standard test includes 15-20 basic parameters (total cholesterol, glucose, full blood count). A longevity-focused test adds 12-15 markers that predict your biological age and disease risk decades before symptoms appear.
In this guide you'll learn which biomarkers to specifically request from your doctor, how to interpret them beyond 'normal' ranges (which are often simply 'average'), and how frequently to retest. We'll also explore which advanced tests are worth the investment and which are expensive marketing.
Standard reference ranges reflect population averages, not optimal values for longevity
TL;DR: The essentials of longevity blood testing
- Standard tests detect disease; longevity tests detect deviation from optimal before pathology exists
- 12 key biomarkers go beyond the basic panel: fasting insulin, homocysteine, high-sensitivity CRP, lipoprotein(a), vitamin D, omega-3 index, amongst others
- Optimal frequency: complete analysis every 6 months if optimising protocols; annually if maintaining
- Interpret in context: a 'normal' value may be far from optimal for longevity
- Cost in the UK: basic analysis through NHS; advanced biomarkers £60-120 privately
What a standard blood test measures (and what you miss)
When you request 'a blood test' at your surgery, you typically receive:
Basic metabolic panel: glucose, creatinine, uric acid, liver enzymes (ALT, AST), bilirubin
Lipid profile: total cholesterol, HDL, LDL, triglycerides
Full blood count: red cells, white cells, platelets, haemoglobin, haematocrit
Thyroid function (sometimes): TSH
This panel is designed to detect established pathology: diabetes (glucose >126 mg/dL), kidney disease (elevated creatinine), liver problems (high transaminases).
What it does NOT detect:
- Early insulin resistance (years before diabetes)
- Chronic low-grade inflammation
- Nutritional deficiencies that accelerate ageing
- Oxidative stress markers
- Cardiovascular risk beyond basic cholesterol
The difference isn't mere preference. Meta-analyses published in The Lancet and JAMA show that biomarkers such as fasting insulin, high-sensitivity CRP and homocysteine predict cardiovascular events 5-10 years earlier than LDL cholesterol alone.
The 12 biomarkers you should add to your test
These markers have solid evidence backing and your doctor can justify including them clinically. Not all are covered by the NHS, but private tests cost £4-12 each.
1. Fasting insulin
Why it matters: insulin resistance appears 10-15 years before fasting glucose becomes abnormal. It's the first domino to fall in metabolic syndrome, type 2 diabetes, and accelerates cellular ageing.
Standard range: 2-25 μU/mL
Optimal longevity range: <7 μU/mL
How to interpret: if your insulin is 15 μU/mL but your glucose is 'normal' (90 mg/dL), your pancreas is already working harder to keep blood sugar controlled. That's early resistance.
2. Glycated haemoglobin (HbA1c)
Measures your average glucose over the last 3 months, not just the single fasting value.
Standard range: <5.7%
Optimal range: <5.3%
Prospective studies show each 0.5% increase in HbA1c increases cardiovascular risk by 18%, even within the 'non-diabetic' range.
3. High-sensitivity C-Reactive Protein (hs-CRP)
The most validated marker of chronic inflammation. Low-grade inflammation accelerates all ageing processes.
Standard range: <10 mg/L
Optimal range: <1 mg/L
High risk: >3 mg/L
If your hs-CRP is 2.5 mg/L, you're in 'normal' range but with moderate inflammation. Sources include: pro-inflammatory diet, visceral obesity, insufficient sleep, chronic stress, dysbiotic microbiota.
4. Homocysteine
An amino acid that at elevated levels damages vascular endothelium and associates with cognitive decline.
Standard range: <15 μmol/L
Optimal range: <8 μmol/L
Elevated homocysteine usually indicates deficiency of vitamins B6, B9 (folate) and B12, all critical for methylation and DNA repair.
5. Lipoprotein(a) Lp(a)
A cholesterol particle genetically determined that increases cardiovascular risk independently of your LDL.
Measure once in your lifetime (doesn't change with diet or exercise).
High risk: >50 mg/dL or >125 nmol/L
If your Lp(a) is high, you need to be more aggressive optimising other risk factors.
6. ApoB (Apolipoprotein B)
Measures the total number of atherogenic particles, not just their cholesterol content. Superior to LDL for predicting cardiovascular risk.
Optimal range: <80 mg/dL
Aggressive target (primary prevention): <60 mg/dL
7. Vitamin D (25-OH)
60-80% of the UK population has suboptimal levels, especially in winter.
Standard range: >20 ng/mL (deficiency <20)
Optimal range: 40-60 ng/mL
Below this level, vitamin D transitions from a bone regulator to a hormone that modulates immunity, inflammation and expression of over 200 genes.
8. Omega-3 Index
Measures the percentage of EPA+DHA in red blood cell membranes. Reflects your omega-3 intake over the last 3-4 months.
Optimal range: >8%
High risk: <4%
In the UK, where consumption of oily fish has declined, many people are below 6% unknowingly.
9. Ferritin
A marker of iron stores. Both deficiency and excess are problematic.
Optimal range men: 50-150 ng/mL
Optimal range women premenopausal: 30-100 ng/mL
Optimal range women postmenopausal: 50-120 ng/mL
Ferritin >200 ng/mL in men may indicate iron overload (pro-oxidant). Ferritin <30 affects energy, thyroid function and cognitive performance.
10. Complete thyroid profile
Not just TSH. Request:
- TSH: 0.5-2.5 mU/L (optimal for longevity, not the wider 0.4-4.5 range)
- Free T4: upper half of range
- Free T3: upper half of range
- Thyroid antibodies (anti-TPO, anti-Tg): if suspecting autoimmunity
Suboptimal thyroid function (subclinical hypothyroidism) accelerates slow metabolism, weight gain, brain fog.
11. Testosterone total and free (men >35 years)
Low testosterone in men isn't just about libido. It affects muscle mass, bone density, body composition, cognitive function.
Optimal range: >500 ng/dL (total), >10 ng/dL (free)
If low, also request LH and FSH to distinguish primary (testicular) from secondary (pituitary) hypogonadism.
12. SHBG (Sex Hormone Binding Globulin)
A protein that binds testosterone and oestrogens, regulating how much is 'free' (active).
High SHBG: less active hormone available
Low SHBG: associated with insulin resistance, fatty liver
How to request these tests from your doctor in the UK
The NHS covers biomarkers with clinical justification. Your GP can request:
Covered without issue: glucose, HbA1c, complete lipid profile (including ApoB in many regions), hs-CRP, homocysteine (if cardiovascular history), vitamin D, ferritin, complete thyroid.
More difficult: fasting insulin (justify by suspecting resistance), Lp(a) (once, justifying cardiovascular family history), omega-3 index (private, £40-50).
Complete private option: £90-140 in private laboratories such as Medichecks, Thriva, LDN Messenger. Includes all these biomarkers.
::flow-steps{steps='1. Book appointment with GP 2 weeks ahead, 2. List specific markers with justification (family history, health optimisation), 3. If NHS won't cover, ask private cost at same lab, 4. Fast 10-12h before testing, 5. Collect results and request digital copy for tracking'} ::
Practical tip: bring a printed version of this article or notes with exact biomarker names. Facilitates discussion and demonstrates you've researched.
Beyond blood: advanced biomarkers worth considering
Once your basic tests are optimised, these second-line investigations add valuable information:
CAC Score (coronary artery calcium)
CT scan of coronary arteries measuring atherosclerotic plaque calcification. The single best individual predictor of cardiovascular risk.
When to do it: >40 years with risk factors (family history, high ApoB, high Lp(a))
Cost: £120-200 private
Frequency: every 3-5 years if score >0
VO₂ max (maximal oxygen uptake)
Measures your actual cardiovascular capacity, not estimated. One of the most powerful mortality predictors.
Where: sports centres with cardiopulmonary testing
Cost: £60-120
High VO₂ max (>45 mL/kg/min in men, >35 in women) reduces all-cause mortality more than any drug.
Body composition by DEXA
Measures muscle mass, visceral fat and bone density with millimetre precision. Your scales and mirror won't give you this.
Frequency: every 6-12 months if optimising composition
Cost: £50-80
How to interpret your results: optimal versus normal
Laboratory reference ranges are calculated from the 2.5-97.5 percentile of people getting tested. That includes obese individuals, sedentary people, those with poor diets.
'Normal' is not synonymous with 'optimal for longevity'.
Real example:
- Fasting glucose: standard range 70-100 mg/dL. Your result: 98 mg/dL → 'normal'.
- Optimal longevity range: <90 mg/dL. You're in grey zone.
- Insulin: 18 μU/mL → 'normal' (range to 25), but optimal is <7. You have early resistance.
This pattern (high-normal glucose + elevated-normal insulin) is compensatory hyperinsulinaemia, the first step toward metabolic syndrome.
How to act:
- Compare against optimal ranges, not just 'normal'
- Look at trends: has your HbA1c risen from 5.1% to 5.4% over 2 years? Though both 'normal', the trend matters
- Cross-reference biomarkers: high hs-CRP + high ApoB + high insulin → pro-inflammatory profile accelerating atherosclerosis
Testing frequency: when to retest
Complete analysis (30-35 parameters):
- Every 6 months if implementing protocols (diet, exercise, supplementation) and measuring impact
- Every 12 months once optimised and maintaining habits
- Every 3-4 months if high-risk biomarkers (HbA1c >5.7%, hs-CRP >3, ApoB >100) with aggressive intervention
Biomarkers you don't need to repeat:
- Lp(a): once in lifetime
- CAC score: every 3-5 years (progresses slowly)
- Genetics (ApoE, SNPs): once
Optimal timing for testing:
- Fast 10-12 hours (water only)
- Same time of day (ideally 8-9 am)
- Avoid intense exercise 48h before (elevates CPK, alters cortisol)
- Well hydrated but not excessively (prevents sample dilution)
From biomarkers to action: using your results
A blood test without an action plan is just a PDF on your computer. Data alone doesn't improve health; the decisions you make with it do.
If your insulin is 12-18 μU/mL (early resistance):
- Diet: reduce processed carbohydrates, increase protein and fibre
- Exercise: resistance training 3x/week (increases muscle insulin sensitivity)
- Fasting: try 12-14 hour eating windows (e.g. dinner 21:00, breakfast 10:00)
- Retest in 3 months to see progress
If your hs-CRP is >2 mg/L (chronic inflammation):
- Identify sources: excess weight (adipose tissue releases cytokines), ultra-processed foods, insufficient sleep, chronic stress
- Omega-3: 2-3g EPA+DHA daily (oily fish or supplement)
- Polyphenols: plant-rich diet with berries, leafy greens, green tea
- Optimise sleep: chronic sleep deprivation raises hs-CRP 40-50%
If your vitamin D is <30 ng/mL:
- Supplement: 2000-4000 IU daily (with fat-containing meal)
- Sunlight: 15-20 minutes exposure on arms/legs without protection, 3-4x weekly (spring-summer)
- Retest in 2-3 months and adjust dose to maintain 40-60 ng/mL
Choosing a solid supplementation protocol
Once you know your suboptimal biomarkers, temptation is to buy 15 bottles of supplements. Here's the problem: most supplements on the market contain insufficient doses or cheap forms with poor absorption.
Example: a standard multivitamin with 400 IU vitamin D won't correct a 22 ng/mL deficiency. You need 2000-4000 IU daily for months.
Criteria for choosing well:
- Clinical doses: those used in studies, not 'token' amounts
- Bioavailable forms: magnesium glycinate vs oxide, vitamin D3 vs D2, methylated folate vs folic acid
- GMP certification: guarantee label matches contents
- No unnecessary fillers: zero titanium dioxide, excess magnesium stearate, synthetic dyes
At Longevitalis we've developed complementary protocols with exactly this in mind:
- LongeviSleep for overnight repair (magnesium glycinate 300mg, glycine 3g, apigenin)
- Vitalis Renew+ for morning cellular renewal (NAD+ precursors, resveratrol, quercetin)
- LongeviSkin for skin health from within (hydrolysed collagen types I+III, hyaluronic acid, astaxanthin)
All with clinical doses, formulated in the UK under GMP, only evidence-backed ingredients. Zero 'miracle ingredient' marketing, zero homeopathic doses.
Consult your blood test with a professional and decide which protocols match your biomarkers.
Side effects and precautions when interpreting tests
False positives/negatives:
- Dehydration: concentrates all values (haemoglobin, creatinine appear elevated)
- Recent intense exercise: raises CPK, myoglobin, alters cortisol
- Acute infection: spikes hs-CRP, white cells (wait 2-3 weeks after cold)
- Menstrual cycle: ferritin and haemoglobin vary by phase
Common interpretation mistakes:
- Correlation isn't causation: high hs-CRP may reflect chronic inflammation OR a mild infection you forgot about
- Single marker: one isolated biomarker rarely tells the whole story. You need complete context
- Over-reacting: one slightly abnormal result in a single test isn't diagnostic. Retest before major protocol changes
When to consult a specialist:
- Significant abnormalities: HbA1c >6%, elevated creatinine, transaminases >2x upper limit
- Contradictory results difficult to interpret
- Before starting high-dose supplementation if taking medication
FAQ: Frequently asked questions about longevity blood testing
How much does a complete longevity blood test cost in the UK?
NHS with clinical justification is free or minimal charge depending on region. Complete private test (30-35 biomarkers): £90-140 at private laboratories like Medichecks or Thriva. Individual biomarkers added: £4-12 each.
Can I get blood tests without a doctor's prescription?
Yes. Many private laboratories allow direct access without prescription. Medichecks, Thriva and others offer 'health packages' you can order online. Professional interpretation is still recommended.
Does intermittent fasting affect blood test results?
If you practise intermittent fasting regularly, your tests reflect that metabolic state (which is precisely what you want to measure). Maintain your usual fasting protocol before testing. Don't change your routine just for the test or you'll falsify your 'real' state.
How often should I retest vitamin D if supplementing?
Test baseline before starting, retest at 2-3 months to adjust dose, then every 6-12 months for maintenance. Once in optimal range (40-60 ng/mL), levels drop slowly if you maintain supplementation.
Are genetic tests (ApoE, longevity SNPs) worth it?
Depends on your goal. ApoE is useful if you have Alzheimer's family history (ApoE4 increases risk). Methylation SNPs (MTHFR) can explain high homocysteine. But genetics show risk, not destiny. Blood biomarkers show your current state, which you can modify. Prioritise blood tests; genetics is second-level.
Can I compare results from different laboratories?
With caution. Analysis methods vary slightly between labs. To track trends over time, use the same laboratory consistently. Reference ranges also differ between labs.
Conclusion: from data to real longevity
A longevity blood test isn't an annual ritual to 'check everything's fine'. It's your biological dashboard, the telemetry showing whether your protocols work or need adjustment.
The biomarkers you've learned here—fasting insulin, homocysteine, hs-CRP, ApoB, vitamin D, omega-3 index—predict your health trajectory 5-15 years before symptoms or diagnosable disease appear.
Reactive medicine waits for something to break. Preventive medicine measures, optimises and retests. You don't need to be a doctor to understand your biomarkers, but you do need to specifically request them, interpret them in longevity context (not just 'normal'), and act accordingly.
Start with your next test. Bring this article to your GP, add the 12 key biomarkers, compare against optimal ranges. Then in 6-12 months, retest. Blood tests that aren't repeated don't measure progress, only resolve single-point doubts.
Your biological age isn't determined by your date of birth. It's determined by daily decisions backed by data.
Disclaimer: This information is educational and doesn't replace professional medical advice. Consult your doctor before starting any protocol, especially if taking medication or with pre-existing conditions. Biomarkers should be interpreted in individual clinical context, not in isolation.
