Which blood biomarkers actually matter for longevity?

Short answer: there’s no single “longevity” blood test. But several routinely measured biomarkers are strongly tied to long-term mortality and age-related disease risk — and they’re actionable. Below I list the highest‑value markers, what they indicate, rough “good” targets used in longevity medicine, how often to check them, and a few reputable labs/services you can use.

Highest‑value biomarkers (why they matter and practical targets)

• Lipids / atherosclerosis risk
  • LDL‑cholesterol (and non‑HDL): main driver of atherosclerotic cardiovascular disease. Lower is usually better for longevity. Practical targets: LDL <100 mg/dL for most people; <70 mg/dL if high risk. Non‑HDL <130 mg/dL.
  • Apolipoprotein B (ApoB): better predictor than LDL mass for particle number. ApoB <80 mg/dL is commonly used as a target.
  • Lipoprotein(a) [Lp(a)]: genetically determined risk factor — high Lp(a) markedly raises CVD risk; measured once to know baseline.
• Glycemia / metabolic health
  • HbA1c: long‑term glucose control. Higher levels predict diabetes and vascular disease. Aim <5.7% for normal; many longevity clinicians prefer <5.5% if safe.
  • Fasting glucose, fasting insulin, HOMA‑IR: help catch insulin resistance earlier than A1c.
• Inflammation & immune activation
  • High‑sensitivity CRP (hs‑CRP): a robust predictor of cardiovascular events and mortality. Desirable <1 mg/L; 1–3 moderate; >3 high.
  • (Research/optional) IL‑6 and TNFα are informative but less available clinically.
• Kidney & filtration markers
  • Serum creatinine / eGFR: chronic kidney disease increases mortality risk.
  • Cystatin C: more sensitive eGFR marker in some people and useful for combined eGFR equations.
  • Urine albumin/creatinine ratio: early kidney damage predictor.
• Liver health / metabolic stress
  • ALT, AST, GGT: elevated GGT especially correlates with metabolic disease and mortality risk.
• Hematology & frailty signals
  • Complete blood count (CBC), especially hemoglobin and RDW (red cell distribution width). High RDW consistently predicts higher mortality and frailty.
• Cardiac stress
  • NT‑proBNP or BNP: sensitive for occult heart strain/failure and predictive of outcomes even at “low” elevations.
• Nutrition / modifiable deficiencies
  • 25‑hydroxy vitamin D (target commonly 30–50 ng/mL), B12, ferritin (iron stores) — extremes relate to poor outcomes.
• Thyroid
  • TSH (with free T4/free T3 as needed): both low and high thyroid function affect aging/metabolism.
• Coagulation markers (in some situations)
  • D‑dimer, fibrinogen: higher levels associate with clotting risk and mortality in older adults.
• Advanced/optional markers for a deeper view
  • ApoB particle count, advanced lipoprotein testing. Lp‑PLA2, lipoprotein subfractions.
  • Telomere length and epigenetic clocks (DNAm GrimAge, Horvath clocks): give a biological‑aging estimate (research/interpretive, not diagnostic).
  • Proteomics/metabolomics (e.g., SomaLogic, Nightingale) can predict risk decades ahead but are mainly for research/precision programs.

Which tests and services to use (reputable options)

• Clinical labs (standard, clinician‑grade)
  • Quest Diagnostics and Labcorp — broad menu (lipids, ApoB, hs‑CRP, HbA1c, cystatin C, NT‑proBNP, vitamins).
  • Your local hospital/academic center for specialty tests and nephrology/cardiology follow‑up.
• Consumer/precision wellness services (good for integrated interpretation)
  • InsideTracker — aggregates labs, gives personalized targets and lifestyle interventions.
  • Thorne WellConnect — at‑home sample kits tied to practitioners and actionable plans.
  • Everlywell / LetsGetChecked — convenient at‑home collection for core panels, but verify what’s included.
• Advanced aging / research‑grade tests
  • TruDiagnostic (epigenetic clocks), Life Length / TeloYears (telomere length), and SomaLogic or Nightingale Health for proteomics/metabolomics.

How often to test

• Baseline: get a comprehensive baseline (CBC, CMP, lipid panel + ApoB/Lp(a), hs‑CRP, HbA1c, fasting glucose+insulin, vitamin D, TSH, urine albumin).
• Routine: annually for most healthy adults; every 3–6 months if you’re changing therapy (statins, weight loss, glucose management) or if abnormalities exist.
• Advanced tests (epigenetic/proteomic): once yearly or as recommended by the testing service — they’re best used to track trends over time.

What to do with abnormal results

• Most of these markers are modifiable: diet (Mediterranean/plant‑forward), exercise (aerobic + resistance), sleep, smoking cessation, weight loss, and blood‑pressure control lower risk across markers.
• Medications (e.g., statins, antihypertensives, metformin) can be highly effective where appropriate — discuss with a clinician.
• Recheck after lifestyle changes or treatment adjustments to confirm improvement.

Caveats

• Biomarkers are risk indicators, not guarantees. They must be interpreted in context (age, sex, family history, medications).
• Some advanced tests are still research-focused and add cost without clear, evidence‑based interventions.
• Always review results with a qualified clinician before starting or stopping medications.

If you want, I can:

• Suggest a single “starter” lab panel you can order now (exact test names and typical targets), or
• Recommend which advanced test(s) make sense given your age, family history, and current health.