Biomarker Encyclopedia

Understand what each biomarker measures, optimal ranges, and why it matters for your longevity.

ApoB

Cardiovascular

Measures the number of atherogenic lipoprotein particles in your blood — one per LDL, VLDL, and Lp(a) particle.

Optimal: < 80 mg/dL (optimal) · < 60 mg/dL (aggressive)

Lp(a)

Cardiovascular

Lipoprotein(a) — a genetically determined lipoprotein that is a potent driver of atherosclerosis and thrombosis.

Optimal: < 30 nmol/L (low risk) · > 125 nmol/L (high risk)

LDL-C

Cardiovascular

Low-density lipoprotein cholesterol — the traditional measure of 'bad' cholesterol concentration.

Optimal: < 100 mg/dL (standard) · < 70 mg/dL (high risk)

LDL-P

Cardiovascular

LDL particle number — counts the actual number of LDL particles, regardless of the cholesterol they carry.

Optimal: < 1000 nmol/L (optimal) · < 1300 nmol/L (normal)

HDL-C

Cardiovascular

High-density lipoprotein cholesterol — involved in reverse cholesterol transport from arteries back to the liver.

Optimal: > 50 mg/dL (men) · > 60 mg/dL (women)

Triglycerides

Metabolic

Fat molecules circulating in your blood, strongly linked to diet, insulin resistance, and metabolic health.

Optimal: < 100 mg/dL (optimal) · < 150 mg/dL (normal)

hsCRP

Inflammatory

High-sensitivity C-reactive protein — a liver-produced marker of systemic inflammation.

Optimal: < 1.0 mg/L (optimal) · > 3.0 mg/L (high risk)

Lp-PLA2

Inflammatory

Lipoprotein-associated phospholipase A2 — an enzyme specific to vascular inflammation.

Optimal: < 200 ng/mL (optimal)

Fibrinogen

Inflammatory

A blood-clotting protein that also serves as an acute-phase inflammatory marker.

Optimal: 200-300 mg/dL (optimal) · > 400 mg/dL (elevated)

Homocysteine

Cardiovascular

An amino acid intermediate in methionine metabolism — elevated levels damage blood vessel walls.

Optimal: < 10 μmol/L (optimal) · > 15 μmol/L (elevated)

HbA1c

Metabolic

Glycated hemoglobin — reflects your average blood sugar levels over the past 2-3 months.

Optimal: < 5.4% (optimal) · 5.7-6.4% (prediabetic)

Fasting Glucose

Metabolic

Blood sugar level measured after an overnight fast — a basic but important metabolic marker.

Optimal: 72-85 mg/dL (optimal) · < 100 mg/dL (normal)

Fasting Insulin

Metabolic

Insulin levels after fasting — one of the earliest indicators of insulin resistance, years before glucose rises.

Optimal: 2-6 μIU/mL (optimal) · < 10 μIU/mL (normal)

TSH

Hormonal

Thyroid-stimulating hormone — the primary screening marker for thyroid function and metabolic rate.

Optimal: 0.5-2.5 mIU/L (optimal) · 0.4-4.0 mIU/L (lab range)

Free T3

Hormonal

The active thyroid hormone — directly regulates metabolic rate, energy production, and body temperature.

Optimal: 3.0-4.0 pg/mL (optimal)

Free T4

Hormonal

Thyroxine — the main thyroid hormone produced by the thyroid gland, converted to active T3 in tissues.

Optimal: 1.0-1.5 ng/dL (optimal)

Total Testosterone

Hormonal

Primary androgen hormone — critical for muscle mass, bone density, energy, mood, and cardiovascular health.

Optimal: 500-900 ng/dL (men) · 15-70 ng/dL (women)

Estradiol

Hormonal

The primary estrogen — essential for bone health, cardiovascular protection, brain function, and reproductive health.

Optimal: 20-30 pg/mL (men) · Varies by cycle phase (women)

DHEA-S

Hormonal

Dehydroepiandrosterone sulfate — the most abundant steroid hormone and a precursor to both testosterone and estrogen.

Optimal: 200-400 μg/dL (age-adjusted optimal)

Cortisol

Hormonal

The primary stress hormone — regulates metabolism, immune function, and the body's fight-or-flight response.

Optimal: 6-18 μg/dL (morning, optimal) · Context-dependent

IGF-1

Hormonal

Insulin-like growth factor 1 — a growth hormone mediator involved in tissue repair, muscle growth, and cellular aging.

Optimal: 100-200 ng/mL (longevity-optimal range)

Vitamin D

Nutritional

25-hydroxyvitamin D — a steroid hormone essential for bone health, immune regulation, and mood.

Optimal: 40-60 ng/mL (optimal) · 30-100 ng/mL (sufficient)

Vitamin B12

Nutritional

Essential for nerve function, DNA synthesis, and red blood cell formation — deficiency is common, especially after age 50.

Optimal: > 500 pg/mL (optimal) · 200-900 pg/mL (lab range)

Folate

Nutritional

Vitamin B9 — critical for DNA methylation, cell division, and homocysteine metabolism.

Optimal: > 10 ng/mL (optimal) · 3-20 ng/mL (lab range)

Omega-3 Index

Nutritional

Measures EPA and DHA as a percentage of total red blood cell fatty acids — a direct indicator of omega-3 status.

Optimal: 8-12% (optimal) · < 4% (high risk)

Magnesium (RBC)

Nutritional

Red blood cell magnesium — a more accurate measure of magnesium status than serum magnesium.

Optimal: 5.0-6.5 mg/dL (optimal)

Ferritin

Nutritional

Iron storage protein — reflects total body iron stores and serves as an inflammatory marker.

Optimal: 40-100 ng/mL (men) · 30-80 ng/mL (women)

Zinc

Nutritional

An essential trace mineral involved in immune function, wound healing, DNA synthesis, and over 100 enzymatic processes.

Optimal: 80-120 μg/dL (optimal)

ALT

Organ Function

Alanine aminotransferase — a liver enzyme that leaks into the blood when liver cells are damaged.

Optimal: < 25 U/L (optimal) · < 40 U/L (lab range)

GGT

Organ Function

Gamma-glutamyl transferase — a liver and bile duct enzyme that also reflects oxidative stress.

Optimal: < 25 U/L (optimal) · < 50 U/L (lab range)

eGFR

Organ Function

Estimated glomerular filtration rate — measures how well your kidneys filter waste from the blood.

Optimal: > 90 mL/min (optimal) · 60-89 (mild decline)

Uric Acid

Organ Function

A byproduct of purine metabolism — both a marker of metabolic health and, when elevated, a driver of gout and kidney disease.

Optimal: 3.5-5.5 mg/dL (optimal) · < 7.0 mg/dL (lab range)

Telomere Length

Aging

Measures the length of protective caps on chromosome ends — a marker of cellular aging and replicative capacity.

Optimal: Age-adjusted percentile (>50th = favorable)

Epigenetic Age (DNA Methylation)

Aging

Biological age calculated from DNA methylation patterns — the most scientifically validated measure of how fast you are aging.

Optimal: Biological age < chronological age (favorable)

Naïve T-Cells

Aging

Immune cells that have not yet encountered an antigen — their decline is a hallmark of immune aging (immunosenescence).

Optimal: Age-adjusted percentile (higher = younger immune system)

GRAIL Galleri (Multi-Cancer Early Detection)

Cancer Screening

A blood test that screens for over 50 types of cancer by detecting cell-free DNA shed by tumors into the bloodstream.

Optimal: No cancer signal detected (favorable)

APOE Genotype

Genetic

Apolipoprotein E gene variants (ε2, ε3, ε4) — the strongest common genetic risk factor for Alzheimer's disease.

Optimal: ε3/ε3 (neutral risk) · ε4 carriers at elevated risk

MTHFR Variants

Genetic

Methylenetetrahydrofolate reductase gene variants — affect folate metabolism and methylation capacity.

Optimal: Wild type (no variants) · C677T/A1298C variants are common

Pharmacogenomics Panel

Genetic

Tests how your genes affect drug metabolism — enabling personalized medication selection and dosing.

Optimal: Variants in CYP2D6, CYP2C19, CYP3A4, etc.

Whole Genome Sequencing

Genetic

Comprehensive analysis of your entire ~3 billion base pair genome — the most complete genetic test available.

Optimal: Identification of pathogenic variants and risk alleles

Whole-Body MRI

Imaging

Non-invasive, radiation-free scan of the entire body — screens for tumors, organ abnormalities, and structural changes.

Optimal: No significant findings (favorable)

CT Coronary Angiography (with AI)

Imaging

High-resolution CT scan of coronary arteries — measures both hard (calcified) and soft (vulnerable) plaque using AI analysis.

Optimal: No significant stenosis or vulnerable plaque

Coronary Artery Calcium (CAC) Score

Imaging

Low-dose CT scan quantifying calcified plaque in coronary arteries — a powerful predictor of future cardiac events.

Optimal: 0 (ideal) · 1-100 (mild) · >400 (severe)

DEXA Scan

Imaging

Dual-energy X-ray absorptiometry — the gold standard for measuring bone density, body composition, and visceral fat.

Optimal: T-score > -1.0 (bone) · ALMI and visceral fat within range

Echocardiogram

Imaging

Ultrasound of the heart — assesses chamber size, valve function, ejection fraction, and diastolic function.

Optimal: Ejection fraction 55-70% · Normal diastolic function

VO2 Max

Functional

Maximum rate of oxygen consumption during exercise — the single strongest predictor of all-cause mortality.

Optimal: Top 25th percentile for age and sex (elite: >50 mL/kg/min)

Gut Microbiome Analysis

Functional

Stool-based sequencing of gut bacteria, fungi, and metabolites — assesses microbial diversity and function.

Optimal: High diversity · Low pathogenic load · Adequate butyrate producers