Read Your Blood Test Like a Longevity Doctor: 23 Biomarkers Decoded with Optimal Ranges
You handed your annual bloodwork to your GP. They glanced at it for ninety seconds and said the four words you've heard for a decade: "Everything looks normal."
You don't feel normal. You feel flat by 3 p.m., your recovery is slipping, your father had his first stent at 58, and something in your gut tells you that "normal" is not the same as "optimal."
You're right. The reference ranges printed on your lab report were built in the 1990s to detect overt disease in a sick population — not to optimize healthspan in a high-performing 42-year-old. The gap between "not sick" and "biologically thriving" is where most longevity is won or lost. HbA1c "normal" stops at 5.7%; the longevity target is under 5.3%. ApoB "normal" stops at 130 mg/dL; the primary-prevention target is under 60. Same blood, two completely different verdicts.
This guide decodes the 23 biomarkers that actually predict how you'll feel at 70, with the optimal range next to the reference range so you can finally read your panel with the eyes of a longevity-trained clinician.
Reference range vs optimal range — why the gap exists
Lab reference ranges are a statistical artifact, not a health target. They are built by sampling a population of patients who walked into a clinic, removing the top 2.5% and bottom 2.5%, and calling the middle 95% "normal." If the sampled population is metabolically average — and in 2026 the average American adult has insulin resistance, low vitamin D, and subclinical inflammation — then "normal" simply describes the middle of a sick distribution.
This is the point Peter Attia has made for years: a reference range tells you what the population looks like, not what you should look like. A fasting glucose of 99 mg/dL is "normal" by every American lab. It is also, biochemically, prediabetes one point away from a formal diagnosis [1]. The reference flagged it as fine. Your pancreas disagrees.
Optimal ranges are different. They are derived from longitudinal outcomes data — the values associated with the lowest 10-year risk of cardiovascular events, cancer, all-cause mortality, and cognitive decline. They ask a different question: not "is this person sick today?" but "where would this number need to be for the next forty years to go well?"
The shift matters most for the executive cohort. You are not trying to avoid a hospitalization next quarter. You are trying to compress morbidity into the last six months of a 95-year life. That requires reading every biomarker against the optimal column — and treating anything in the upper tertile of the reference range as a yellow flag, not a green light.
The 23 biomarkers that actually matter
Below are the 23 markers a longevity-oriented panel should cover, grouped into five categories. For each: what it measures, the standard reference range, the optimal range, and what suboptimal signals.
A consolidated table follows the category breakdown.
Metabolic (5)
HbA1c — Three-month average blood glucose, measured as the percentage of glycated hemoglobin. Reference: <5.7%. Optimal: <5.3%. Suboptimal HbA1c (5.3–5.6%) means you are spending too much time above 140 mg/dL postprandially, accelerating glycation of collagen, LDL, and neuronal proteins. It is the single best inexpensive proxy for metabolic trajectory.
Fasting glucose — Plasma glucose after 12 hours without food. Reference: 70–99 mg/dL. Optimal: 75–90 mg/dL. A fasting glucose of 95 is technically "normal" but signals that hepatic glucose output is no longer being suppressed properly overnight — an early sign of insulin resistance.
Fasting insulin — The hormone, not the substrate. Reference: 2–25 µIU/mL (absurdly wide). Optimal: 2–5 µIU/mL. Insulin rises years before glucose does. A fasting insulin of 12 with a glucose of 88 is a metabolically compensating pancreas — it is working overtime to keep your "normal" glucose normal.
HOMA-IR — Calculated as (fasting glucose × fasting insulin) / 405. Reference: <2.5. Optimal: <1.0. The most actionable single number for insulin sensitivity in a primary-care setting.
Triglycerides — Circulating fat. Reference: <150 mg/dL. Optimal: <80 mg/dL, with a TG/HDL ratio under 1.5. Elevated triglycerides are a louder signal of insulin resistance than fasting glucose itself.
Lipids (4)
ApoB — Apolipoprotein B, one molecule per atherogenic particle (LDL, VLDL, IDL, Lp(a)). Reference: <130 mg/dL. Optimal: <60 mg/dL for primary prevention, <50 mg/dL for secondary. This is the single most important number on your lipid panel — see the dedicated section below.
LDL-C — Cholesterol mass inside LDL particles, usually estimated. Reference: <100 mg/dL. Optimal: <70 mg/dL. Useful but inferior to ApoB when the two disagree (which they do roughly 20% of the time, especially in metabolic syndrome).
HDL-C — Cholesterol carried by HDL. Reference: >40 mg/dL men, >50 mg/dL women. Optimal: 50–80 mg/dL. Higher is not always better — extremely high HDL (>100) is associated with elevated mortality in some cohorts and likely reflects dysfunctional HDL particles.
Lp(a) — Lipoprotein(a), a genetically determined atherogenic particle. Reference: <30 mg/dL. Optimal: <30 mg/dL (and ideally <14). Test it once in your life. Roughly 20% of the population has elevated Lp(a) and most do not know it. It independently raises ASCVD risk and is invisible on standard panels.
Inflammation (3)
hs-CRP — High-sensitivity C-reactive protein, a downstream marker of systemic inflammation. Reference: <3.0 mg/L. Optimal: <1.0 mg/L, ideally <0.5. Paul Ridker's JUPITER trial established hs-CRP as a cardiovascular risk modifier independent of LDL [2]. A reading of 2.5 mg/L in an otherwise asymptomatic executive is not "borderline" — it is a quiet fire.
Ferritin (acute phase context) — Ferritin doubles as an inflammation marker because it rises with any acute-phase response. Reference: 30–400 ng/mL men, 15–150 women. Optimal for inflammation read: <150. A ferritin of 380 with a "normal" CRP often means smoldering inflammation that CRP missed.
Homocysteine — An amino acid intermediate that, when elevated, damages endothelium and predicts cognitive decline. Reference: <15 µmol/L. Optimal: <8 µmol/L. Elevated homocysteine usually reflects functional B12, B6, or folate insufficiency — cheap to fix, costly to ignore.
Hormones (5)
TSH — Thyroid stimulating hormone, the pituitary's request for more thyroid output. Reference: 0.4–4.5 mIU/L. Optimal: 0.5–2.0 mIU/L. A TSH of 3.8 is "normal" but is your pituitary shouting at a tired thyroid.
Free T3 — Active thyroid hormone. Reference: 2.0–4.4 pg/mL. Optimal: upper third of range (3.2–4.4). Energy, body temperature, and cognition track free T3 more tightly than TSH.
Free T4 — Storage thyroid hormone. Reference: 0.8–1.8 ng/dL. Optimal: middle to upper third (1.1–1.6).
Total and free testosterone (men, and increasingly women) — Reference (men): 264–916 ng/dL total. Optimal: 600–900 ng/dL total, free testosterone in the upper third of range. A 45-year-old executive with a total testosterone of 320 is "normal" by the lab and biochemically below the median 75-year-old of 1985.
Estradiol (women, cycle-dependent; men, low) — Critical for bone, cognition, and cardiovascular protection in women across the perimenopause transition. Targets are individualized; in men, optimal estradiol is 20–30 pg/mL (too low is as harmful as too high).
Nutrient and healthspan (6)
Vitamin D 25-OH — Reference: 30–100 ng/mL. Optimal: 50–80 ng/mL. The most under-tested high-leverage marker. Sub-50 vitamin D is independently associated with all-cause mortality, autoimmune disease, and impaired immune function.
Vitamin B12 — Reference: 200–900 pg/mL. Optimal: >500 pg/mL. Levels in the 200–400 range are "normal" but functionally deficient — pair with methylmalonic acid if symptomatic.
Ferritin (iron status context) — Optimal for iron status: 50–150 ng/mL. Below 30 in a fatigued woman is a near-certain cause; below 50 with high training load is suboptimal even if "normal."
Magnesium RBC — Red blood cell magnesium, vastly more accurate than serum magnesium (which is tightly regulated and misses tissue depletion). Optimal: 6.0–6.8 mg/dL.
Omega-3 index — Percentage of EPA + DHA in red blood cell membranes. Reference: rarely measured. Optimal: >8%. The single best dietary marker for cardiovascular and cognitive risk; the average Western adult sits at 4–5%.
Uric acid — Often dismissed unless gout appears. Reference: 3.5–7.2 mg/dL men, 2.6–6.0 women. Optimal: <5.5 men, <4.5 women. Elevated uric acid is now understood as a driver of insulin resistance and endothelial dysfunction, not just a gout precursor.
Master table — all 23 biomarkers
| Biomarker | Reference range | Optimal range | What suboptimal signals |
|---|---|---|---|
| HbA1c | <5.7% | <5.3% | Glycation, postprandial spikes |
| Fasting glucose | 70–99 mg/dL | 75–90 mg/dL | Hepatic insulin resistance |
| Fasting insulin | 2–25 µIU/mL | 2–5 µIU/mL | Compensating pancreas |
| HOMA-IR | <2.5 | <1.0 | Whole-body insulin resistance |
| Triglycerides | <150 mg/dL | <80 mg/dL | Metabolic dysfunction |
| ApoB | <130 mg/dL | <60 mg/dL | Atherogenic particle burden |
| LDL-C | <100 mg/dL | <70 mg/dL | Cholesterol mass in LDL |
| HDL-C | >40 / >50 mg/dL | 50–80 mg/dL | Reverse transport capacity |
| Lp(a) | <30 mg/dL | <30 mg/dL (ideal <14) | Genetic ASCVD risk |
| hs-CRP | <3.0 mg/L | <1.0 mg/L | Systemic inflammation |
| Ferritin (inflam) | 30–400 / 15–150 | <150 | Smoldering inflammation |
| Homocysteine | <15 µmol/L | <8 µmol/L | B-vitamin insufficiency, endothelial damage |
| TSH | 0.4–4.5 mIU/L | 0.5–2.0 mIU/L | Subclinical hypothyroidism |
| Free T3 | 2.0–4.4 pg/mL | 3.2–4.4 pg/mL | Low active thyroid |
| Free T4 | 0.8–1.8 ng/dL | 1.1–1.6 ng/dL | Low storage thyroid |
| Total testosterone (M) | 264–916 ng/dL | 600–900 ng/dL | Hypogonadism, low vitality |
| Estradiol (M) | 10–40 pg/mL | 20–30 pg/mL | Bone, mood, libido |
| Vitamin D 25-OH | 30–100 ng/mL | 50–80 ng/mL | Immune, mood, mortality risk |
| Vitamin B12 | 200–900 pg/mL | >500 pg/mL | Functional deficiency |
| Ferritin (iron) | 30–400 / 15–150 | 50–150 ng/mL | Iron insufficiency |
| Magnesium RBC | 4.2–6.8 mg/dL | 6.0–6.8 mg/dL | Tissue depletion |
| Omega-3 index | not standard | >8% | Cardiovascular, cognitive risk |
| Uric acid | 3.5–7.2 / 2.6–6.0 | <5.5 / <4.5 | Insulin resistance driver |
The 5 most important — if you only test these
If budget, access, or sheer overwhelm forces you to a shortlist, here is the ranked priority for an executive who wants maximum signal per dollar.
1. ApoB. Atherosclerotic cardiovascular disease is the leading cause of death in developed economies, and ApoB is the most accurate single number for the particle burden driving it [3]. Optimal: <60 mg/dL. If suboptimal, the response is a combination of dietary saturated fat reduction, fiber load, and — when indicated — statins or PCSK9 inhibitors. Discuss with a clinician.
2. HbA1c. The cheapest, most stable window into your three-month metabolic average. Optimal: <5.3%. If suboptimal, the lever is postprandial glucose control: walk after meals, lower refined carbohydrate density, and consider a two-week continuous glucose monitor to see your own response curves.
3. hs-CRP. Inflammation is the soil in which cardiovascular disease, cancer, and neurodegeneration grow. Optimal: <1.0 mg/L. If elevated, the differential is broad — visceral adiposity, periodontal disease, sleep apnea, autoimmune activity, gut dysbiosis. Investigate.
4. Vitamin D 25-OH. Cheap, easy, and high-leverage across immune function, bone density, mood, and mortality. Optimal: 50–80 ng/mL. If suboptimal, supplement (typically 2,000–5,000 IU daily with K2, with retesting at 90 days).
5. Total testosterone (men) / TSH (everyone). Energy, drive, recovery, and body composition track these closely. A 45-year-old with a "normal" total testosterone of 350 is functionally androgen-deficient by every healthspan standard.
ApoB vs LDL — the fight settled
For two decades, primary care has tracked LDL-cholesterol as the lipid risk number. The science has moved on.
LDL-C measures the mass of cholesterol carried inside LDL particles. ApoB measures the number of atherogenic particles directly — one ApoB molecule per particle, no estimation. Atherosclerosis is caused by particles entering the arterial wall, not by the cholesterol mass they happen to carry. Two patients can have the same LDL-C of 110 mg/dL; one has 800 nmol/L of LDL particles, the other has 1,600. Their cardiovascular risk is not the same.
This is the core argument Allan Sniderman and Michael Pencina have made in a series of meta-analyses: when ApoB and LDL-C disagree, ApoB wins on outcomes prediction every time [3, 4]. The disagreement is most pronounced in patients with metabolic syndrome, type 2 diabetes, and high triglycerides — exactly the population most at cardiovascular risk.
The optimal targets:
- <60 mg/dL for primary prevention in an adult who wants to minimize 30-year ASCVD risk.
- <50 mg/dL for secondary prevention or for adults with elevated Lp(a) or strong family history.
- <80 mg/dL as a permissive ceiling for the average risk-tolerant adult.
If your lab does not report ApoB by default, ask. It is inexpensive, the assay is standardized, and it changes management in roughly 1 in 5 patients.
Reading your panel — the 4-step protocol
Once your bloodwork lands in your inbox, work through it in this order:
Step 1 — Map every value against the OPTIMAL column. Ignore the lab's color coding. The lab is flagging you against the reference range, which is the wrong target. Walk down your results line by line and write the optimal range next to each.
Step 2 — Score each marker as "optimal / borderline / off." Optimal sits within the optimal range. Borderline is in the reference range but outside optimal. Off is outside the reference range entirely. Most executives have 6–10 borderline markers and 1–3 off — and the borderline cluster is usually where the real story lives.
Step 3 — Look for clusters, not single values. A single elevated marker is noise. Patterns are signal:
- 3+ off in metabolic (HbA1c, fasting insulin, HOMA-IR, triglycerides) = early metabolic syndrome.
- 2+ off in inflammation (hs-CRP, ferritin, homocysteine) = chronic systemic inflammation requiring root-cause investigation.
- ApoB high + triglycerides high + HDL low = atherogenic dyslipidemia, the most underdiagnosed lipid pattern in the executive cohort.
- Low free T3 + borderline TSH + low ferritin = functional hypothyroidism, often dismissed.
Step 4 — Re-test in 90 days after intervention. Most biomarkers respond to lifestyle within one quarter. HbA1c reflects 90 days by definition. ApoB shifts within weeks of dietary or pharmacologic change. hs-CRP can normalize in 30 days when the inflammatory driver is removed. Without a re-test, you are guessing.
What annual bloodwork SHOULD include
The standard CBC + comprehensive metabolic panel (CMP) your GP orders is built for disease screening, not optimization. It misses the markers that matter most.
A longevity-oriented annual panel adds:
- ApoB (not LDL-C alone)
- Lp(a) — once in your life, then never again unless on therapy
- hs-CRP (not standard CRP)
- Fasting insulin + HOMA-IR calculation
- Vitamin D 25-OH
- Free T3, free T4 (not TSH alone)
- Total + free testosterone (men, and women over 40)
- Estradiol (men and women)
- Omega-3 index
- Magnesium RBC (not serum magnesium)
- Homocysteine
- Uric acid
The incremental cost over a basic panel is roughly $150–$300 once a year. The incremental signal is the difference between "everything normal" and a real action plan.
Print this list. Hand it to your physician. If they push back, find one who measures what matters.
FAQ
| Question | Answer |
|---|---|
| My doctor said my bloodwork is normal. Why should I question it? | Because "normal" is a statistical category describing the middle 95% of a sampled population — and the population sampled in modern lab data is metabolically average, which in 2026 means insulin-resistant, vitamin D deficient, and inflamed. A reference range tells you what most people look like; it does not tell you what you should look like. Optimal ranges, derived from longevity outcomes data, are typically 30–50% tighter than reference ranges. Your doctor is not wrong — they are using the right tool for disease detection and the wrong tool for healthspan optimization. |
| What's the difference between ApoB and LDL? | LDL-C measures the mass of cholesterol inside LDL particles. ApoB counts the atherogenic particles themselves — one ApoB molecule per particle. Because atherosclerosis is driven by particle entry into the arterial wall (not cholesterol mass), ApoB is a more accurate predictor of cardiovascular risk. When the two disagree — which happens in roughly 20% of patients, especially those with metabolic syndrome — ApoB wins on outcomes [3]. |
| How often should I get bloodwork? | Once per year as a baseline if everything is optimal. Every 3–6 months if you are actively intervening on a suboptimal marker (the re-test interval is what makes interventions accountable). Lp(a) is tested once in a lifetime — it is genetically fixed. |
| Can I order my own blood test? | In most US states and many EU countries, yes. Direct-to-consumer services like Marek Health, Function Health, and InsideTracker offer longevity-oriented panels without requiring a physician requisition. Cost typically ranges from $200 to $500 for a comprehensive panel. The advantage: you get the markers you want. The limitation: you also need someone qualified to interpret them. |
| What if my hs-CRP is 2.5 mg/L — should I worry? | It is "normal" by lab standards (<3.0 mg/L) and far above optimal (<1.0 mg/L). A reading of 2.5 in an asymptomatic adult is a quiet inflammatory signal that warrants investigation, not panic. Common drivers: visceral adiposity, periodontal disease, untreated sleep apnea, gut dysbiosis, low-grade autoimmune activity, recent illness or hard training. Re-test in 30 days after addressing the most likely driver before drawing conclusions. |
What Feroce does with your bloodwork
Upload your lab PDF or take a photo of the printout. Feroce parses every biomarker, maps each value against both the reference range and the optimal range, scores the panel for clusters (metabolic, inflammatory, hormonal, nutrient), and surfaces the 3 highest-leverage interventions for your profile. You get a one-page decoded report instead of a five-page lab printout — and a 90-day re-test plan to make every intervention accountable.
Citations
- American Diabetes Association. Standards of Care in Diabetes — 2024. Diabetes Care 2024;47(Suppl 1). PubMed
- Ridker PM, Danielson E, Fonseca FA, et al. Rosuvastatin to prevent vascular events in men and women with elevated C-reactive protein (JUPITER). N Engl J Med 2008;359:2195–2207. PubMed
- Sniderman AD, Thanassoulis G, Glavinovic T, et al. Apolipoprotein B Particles and Cardiovascular Disease: A Narrative Review. JAMA Cardiol 2019;4(12):1287–1295. PubMed
- Pencina MJ, D'Agostino RB, Zdrojewski T, et al. Apolipoprotein B improves risk assessment of future coronary heart disease. Eur J Prev Cardiol 2015;22(10):1321–1327. PubMed
- Tsimikas S. A Test in Context: Lipoprotein(a): Diagnosis, Prognosis, Controversies, and Emerging Therapies. J Am Coll Cardiol 2017;69(6):692–711. PubMed
- Holick MF. Vitamin D Deficiency. N Engl J Med 2007;357:266–281. PubMed
- Selhub J, Jacques PF, Bostom AG, et al. Association between plasma homocysteine concentrations and extracranial carotid-artery stenosis. N Engl J Med 1995;332:286–291. PubMed
- Harris WS, Tintle NL, Imamura F, et al. Blood n-3 fatty acid levels and total and cause-specific mortality from 17 prospective studies. Nat Commun 2021;12:2329. PubMed
- Kunutsor SK, Apekey TA, Seddoh D. Serum uric acid and metabolic syndrome. Atherosclerosis 2015;240(2):428–433. PubMed
- Bhasin S, Brito JP, Cunningham GR, et al. Testosterone Therapy in Men With Hypogonadism: An Endocrine Society Clinical Practice Guideline. J Clin Endocrinol Metab 2018;103(5):1715–1744. PubMed
- Garber JR, Cobin RH, Gharib H, et al. Clinical Practice Guidelines for Hypothyroidism in Adults. Endocr Pract 2012;18(6):988–1028. PubMed
- Attia P. Outlive: The Science and Art of Longevity. Harmony Books, 2023.
Related reading from the bloodwork hub:
- ApoB Target by Age: A Decade-by-Decade Guide
- The 90-Day Re-Test Protocol: Make Every Lab Accountable
- HbA1c, Fasting Insulin, HOMA-IR: The Metabolic Triad Decoded
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