Medicine reacts. We test for answers.
Most labs tell you whether you're sick. Zaro tells you what's developing, what's at the root, and how your biology is aging, so you can act years before a diagnosis.
No other testing platform offers all three tiers of the cascade. Each level answers a fundamentally different question about your health.
Has something already gone wrong?
Surface
Body Systems Covered
The Science
Surface testing captures what has already crossed clinical thresholds. The markers in this panel are what standard medicine looks at during a routine physical, but most people never get a full panel done. These are the red flags that, if caught early, prevent the most common causes of preventable death: heart disease, type 2 diabetes, thyroid dysfunction, and anemia. Surface is the foundation every adult should have at minimum once a year.
Who It's For
Anyone who has never had comprehensive bloodwork done, adults over 25 who want a baseline, or anyone who has not had labs in over two years. A great starting point for first-time Zaro users.
Biomarkers Included
Metabolic Core
- Comprehensive Metabolic Panel (CMP) — Glucose, BUN, Creatinine, eGFR, BUN/Cr Ratio, Sodium, Potassium, Chloride, CO₂, Calcium, Total Protein, Albumin, Total Bilirubin, ALP, AST, ALT (14 values)
- CBC with Differential — WBC, RBC, Hemoglobin, Hematocrit, MCV, MCH, MCHC, RDW, Platelets, Neutrophils, Lymphocytes, Monocytes, Eosinophils, Basophils + absolute counts (22 values)
- HbA1c (Glycated Hemoglobin)
- Fasting Insulin
- Uric Acid
Heart & Lipids
- Standard Lipid Panel (Total Cholesterol, LDL, HDL, Triglycerides)
- hs-CRP (High-Sensitivity C-Reactive Protein)
Thyroid
- TSH (Thyroid Stimulating Hormone)
Urinalysis
- Complete Urinalysis with Microscopy — Color, Clarity, Specific Gravity, pH, Protein, Glucose, Ketones, Blood, Bilirubin, Urobilinogen, Nitrites, Leukocyte Esterase, WBC/hpf, RBC/hpf (14 values)
Advanced Cardiometabolic
- ApoB (Apolipoprotein B)
Nutrients
- Vitamin D (25-OH)
- Ferritin
Is something developing?
Signal
Body Systems Covered
The Science
Signal markers are the early warning system of modern preventive medicine. While Surface markers respond to disease that has already developed, Signal markers detect the physiological conditions that lead to disease, years or even decades before clinical symptoms appear. Elevated ApoB predicts cardiovascular events long before LDL changes. Fasting insulin rises 10–15 years before HbA1c signals pre-diabetes. Elevated hsCRP identifies systemic inflammation that silently damages organs. Signal is where the real prevention happens.
Who It's For
Health-optimizers, athletes, anyone with a family history of cardiovascular disease or metabolic dysfunction, people in their 30s and 40s who want to get ahead of risks, and anyone who has already done Surface and wants to go deeper.
What Signal Adds
Nutrients
- Vitamin B12
- Iron & TIBC (Iron, Total Iron-Binding Capacity, % Saturation)
- Magnesium
Advanced Cardiometabolic
- Lipoprotein(a) — Lp(a)
- LDL Particle Size & Fractionation (NMR) — LDL-P, Small LDL-P, HDL-P, LDL Size, Large HDL-P (5 values)
- Homocysteine
Extended Thyroid
- Free T3 (Free Triiodothyronine)
- Free T4 (Free Thyroxine)
Hormones
- Testosterone (Total & Free) — Male
- DHEA-S (Dehydroepiandrosterone Sulfate)
- Estradiol (E2) — Female
- FSH (Follicle-Stimulating Hormone) — Female
- LH (Luteinizing Hormone) — Female
- Progesterone — Female
- Cortisol (AM — adrenal function)
Metabolic Depth
- Folate (Serum)
- Zinc
- GGT (Gamma-Glutamyl Transferase — liver stress and alcohol metabolism)
Advanced Kidney
- Microalbumin/Creatinine Ratio (early kidney damage detection, 2 values)
What root causes?
Source
Body Systems Covered
The Science
Source reaches the root causes that Signal does not capture: the upstream hormonal imbalances, autoimmune and inflammatory loads, cellular aging markers, and longevity signals that determine how your body ages. PhenoAge (biological age from blood) and the AHA PREVENT heart age model give you two independent scores of how your biology is aging relative to your chronological age, the most powerful feedback loop available in consumer health today. Source also includes the deep hormonal, adrenal, and nutritional panels that explain why your body is performing the way it is.
Who It's For
Longevity-focused individuals, those with chronic fatigue, hormonal symptoms, or unresolved health issues, people who have completed Signal and want root causes, and anyone seriously committed to optimizing how they age.
What Source Adds
Advanced Cardiometabolic
- Fibrinogen (coagulation and inflammation risk)
- OmegaCheck (Omega-3 Index — EPA%, DHA%, Total Index)
Extended Thyroid
- TPO Antibodies (Thyroid Peroxidase — autoimmune thyroid screen)
- Thyroglobulin Antibodies (autoimmune thyroid screen)
Autoimmune
- ANA with Reflex (Antinuclear Antibody — reflex to titer and pattern if positive)
- ESR (Erythrocyte Sedimentation Rate)
Cognitive Risk
- Vitamin B1 (Thiamine)
Two ages. One clock.
Zaro calculates your Biological Age (PhenoAge), reflecting how old your body actually is based on blood chemistry, and your Heart Age using the AHA PREVENT model. Is your biology aging faster or slower than your birthday suggests?
Chronological Age
38Biological Age
PhenoAge Model
Heart Age
AHA PREVENT
Example output · your results will reflect your actual blood data
A living health score, built on three pillars
Zaro synthesizes bloodwork, wearable signals, and lifestyle into a single score out of 100. It updates continuously and adapts to whatever data you have, no wearable required to get started.
Score Bands
Adaptive weighting
Score adapts automatically as you add data
Full data
Labs + wearable + lifestyle
No wearable
Labs re-weighted with lifestyle
Labs only
Biomarker Score shown
Start knowing your body.
Choose a panel, schedule your blood draw, and get answers that actually explain what is happening inside your body.