| Apolipoprotein B ApoB · Cardiovascular & Lipids | < 90 | < 60 (High Risk: < 50) | Semi-Annually (6 Months) | Direct quantification of total atherogenic particle number. Superior to LDL-C in discordant metabolic phenotypes. |
| Lipoprotein(a) Lp(a) · Cardiovascular & Lipids | < 30 | < 14 (or < 75 nmol/L) | Baseline / Targeted | Genetically determined pro-thrombotic and pro-atherosclerotic variant. Lifelong cardiovascular risk stratification. |
| Low-Density Lipoprotein Cholesterol LDL-C · Cardiovascular & Lipids | < 100 | < 70 (Longevity: < 55) | Semi-Annually (6 Months) | Primary historical lipid target. Underestimates atherogenic particle concentration when particle size is small and dense. |
| High-Density Lipoprotein Cholesterol HDL-C · Cardiovascular & Lipids | 40 - 60 | 50 - 75 | Semi-Annually (6 Months) | Mediator of reverse cholesterol transport. Excessively high levels above 90 mg/dL may reflect dysfunctional pro-inflammatory particles. |
| Fasting Serum Triglycerides TG · Cardiovascular & Lipids | < 150 | < 80 | Semi-Annually (6 Months) | Surrogate marker for circulating triglyceride-rich remnant lipoproteins and hepatic de novo lipogenesis. |
| Apolipoprotein A1 ApoA1 · Cardiovascular & Lipids | 120 - 180 | > 140 | Annually (12 Months) | Primary protein constituent of HDL particles. Essential for computing the atherogenic index ratio ApoB/ApoA1. |
| Remnant Cholesterol Remnant-C · Cardiovascular & Lipids | < 30 | < 15 | Semi-Annually (6 Months) | Calculated as Total Cholesterol minus HDL-C minus LDL-C. Highly atherogenic triglyceride-rich particle fraction. |
| Fasting Serum Insulin Fasting Insulin · Glycemic & Metabolic | 2.6 - 24.9 | 2.0 - 5.0 | Quarterly (90 Days) | Most sensitive early indicator of peripheral insulin resistance, rising up to a decade prior to fasting glucose elevations. |
| Fasting Plasma Glucose FPG · Glycemic & Metabolic | 70 - 99 | 72 - 85 | Quarterly (90 Days) | Basal glycemic control governed by hepatic gluconeogenesis and basal pancreatic beta-cell insulin secretion. |
| Hemoglobin A1c HbA1c · Glycemic & Metabolic | 4.0 - 5.6 | 4.8 - 5.2 | Quarterly (90 Days) | 90-day time-weighted glycemic exposure. Reflects cumulative non-enzymatic glycation of erythrocyte hemoglobin. |
| Homeostatic Model Assessment of Insulin Resistance HOMA-IR · Glycemic & Metabolic | < 2.0 | < 1.0 (Optimal Sensitivity: < 0.8) | Quarterly (90 Days) | Mathematical index derived from fasting insulin and glucose. Quantifies hepatic and peripheral insulin sensitivity. |
| Serum C-Peptide C-Peptide · Glycemic & Metabolic | 1.1 - 4.4 | 1.2 - 2.0 | Annually (12 Months) | Equimolar byproduct of proinsulin cleavage. Accurate measure of endogenous pancreatic beta-cell secretory capacity. |
| Serum Uric Acid Uric Acid · Glycemic & Metabolic | 3.5 - 7.2 | 3.5 - 5.0 | Semi-Annually (6 Months) | End product of purine catabolism. Correlates strongly with hepatic fructose metabolism and endothelial dysfunction. |
| High-Sensitivity C-Reactive Protein hs-CRP · Inflammation & Immune | < 3.0 | < 0.5 (Lowest Risk: < 0.3) | Quarterly (90 Days) | Acute-phase hepatic reactant reflecting systemic micro-vascular endothelial inflammation and atheroma instability. |
| Total Plasma Homocysteine HCY · Inflammation & Immune | < 15.0 | 6.0 - 8.5 | Semi-Annually (6 Months) | Sulfur-containing amino acid intermediary. Elevations cause oxidative endothelial injury and indicate impaired methylation. |
| Serum Ferritin Ferritin · Inflammation & Immune | 30 - 400 (M) / 15 - 150 (F) | 50 - 150 (M) / 40 - 100 (F) | Semi-Annually (6 Months) | Primary intracellular iron storage protein. Also functions as an acute-phase reactant during subclinical inflammation. |
| Plasma Fibrinogen Activity Fibrinogen · Inflammation & Immune | 200 - 400 | 200 - 300 | Annually (12 Months) | Coagulation factor and inflammatory protein. High concentrations elevate blood viscosity and thrombotic risk. |
| Erythrocyte Sedimentation Rate ESR · Inflammation & Immune | 0 - 20 (M) / 0 - 30 (F) | < 10 (M) / < 12 (F) | Semi-Annually (6 Months) | Measures suspension stability of red cells. Complements hs-CRP in screening for systemic rheumatic or autoimmune activity. |
| Serum Cystatin C Cystatin C · Renal & Electrolytes | 0.62 - 1.15 | 0.65 - 0.85 | Semi-Annually (6 Months) | Muscle mass-independent filtration marker. Eliminates creatinine bias in athletic individuals with high muscularity. |
| Estimated Glomerular Filtration Rate (2021 CKD-EPI) eGFR · Renal & Electrolytes | > 60 | > 90 (Longevity: > 100) | Semi-Annually (6 Months) | Fundamental metric of nephron functional capacity and renal microvascular clearance performance. |
| Serum Creatinine Creatinine · Renal & Electrolytes | 0.70 - 1.30 (M) / 0.50 - 1.10 (F) | 0.80 - 1.05 (M) / 0.65 - 0.90 (F) | Semi-Annually (6 Months) | Endogenous byproduct of muscle creatine breakdown. Interpretation requires consideration of dietary protein and lean body mass. |
| Blood Urea Nitrogen BUN · Renal & Electrolytes | 7 - 20 | 10 - 16 | Semi-Annually (6 Months) | Reflects urea excretion, renal perfusion status, catabolic rate, and protein consumption balance. |
| Serum Albumin Albumin · Renal & Electrolytes | 3.5 - 5.2 | 4.5 - 5.0 | Semi-Annually (6 Months) | Key constituent of oncotic pressure and major negative acute-phase protein. Strongly weighted in PhenoAge mortality models. |
| Alanine Aminotransferase ALT · Hepatic & Biliary | 7 - 56 | 12 - 25 (M) / 10 - 20 (F) | Semi-Annually (6 Months) | Cytosolic enzyme highly specific to hepatocytes. Early indicator of hepatic steatosis and non-alcoholic fatty liver disease. |
| Aspartate Aminotransferase AST · Hepatic & Biliary | 10 - 40 | 15 - 25 | Semi-Annually (6 Months) | Mitochondrial and cytosolic enzyme found in liver, cardiac, and skeletal muscle. Ratio with ALT provides structural hepatic insights. |
| Gamma-Glutamyl Transferase GGT · Hepatic & Biliary | 9 - 48 (M) / 9 - 36 (F) | 10 - 20 (M) / 8 - 16 (F) | Semi-Annually (6 Months) | Microsomal enzyme sensitive to biliary stasis, alcohol exposure, oxidative stress, and intracellular glutathione depletion. |
| Alkaline Phosphatase ALP · Hepatic & Biliary | 44 - 147 | 50 - 80 | Semi-Annually (6 Months) | Zinc-dependent enzyme reflecting biliary ductal patency and osteoblastic bone turnover rate. Core variable in PhenoAge. |
| Total Serum Bilirubin TBIL · Hepatic & Biliary | 0.2 - 1.2 | 0.6 - 1.2 | Semi-Annually (6 Months) | Potent endogenous lipid-soluble antioxidant. Modestly higher physiologic values correlate with lower coronary event rates. |
| Thyroid-Stimulating Hormone TSH · Hormonal & Endocrine | 0.45 - 4.50 | 1.00 - 2.00 | Semi-Annually (6 Months) | Pituitary regulator of thyroid gland output. Values above 2.5 uIU/mL frequently signify subclinical metabolic down-regulation. |
| Free Triiodothyronine Free T3 · Hormonal & Endocrine | 2.0 - 4.4 | 3.2 - 4.0 | Semi-Annually (6 Months) | Active cellular thyroid hormone governing mitochondrial uncoupling, basal oxygen consumption, and lipid turnover. |
| Free Thyroxine Free T4 · Hormonal & Endocrine | 0.82 - 1.77 | 1.10 - 1.40 | Semi-Annually (6 Months) | Circulating prohormone reservoir available for peripheral enzymatic deiodination to biologically active Free T3. |
| Total Serum Testosterone Total T · Hormonal & Endocrine | 264 - 916 (M) / 15 - 70 (F) | 600 - 900 (M) / 30 - 55 (F) | Semi-Annually (6 Months) | Primary androgen governing muscle protein synthesis, bone mineral density, erythropoiesis, and neurocognitive vigor. |
| Free Bioavailable Testosterone Free T · Hormonal & Endocrine | 5.0 - 21.0 (M) / 0.3 - 1.9 (F) | 15.0 - 25.0 (M) / 1.0 - 1.8 (F) | Semi-Annually (6 Months) | Unbound, biologically active androgen fraction entering target tissues. Not restricted by Sex Hormone-Binding Globulin. |
| Dehydroepiandrosterone Sulfate DHEA-S · Hormonal & Endocrine | 100 - 450 (M) / 60 - 340 (F) | 250 - 400 (M) / 150 - 280 (F) | Annually (12 Months) | Adrenal androgen precursor displaying progressive age-related decline (adrenopause). Biomarker of adrenal reserve. |
| Insulin-Like Growth Factor 1 IGF-1 · Hormonal & Endocrine | 100 - 300 | 120 - 180 (Longevity) | Annually (12 Months) | Effector of Growth Hormone signaling. Moderate levels balance anabolic tissue repair against mTOR-driven cellular senescence. |
| Hemoglobin Hgb · Hematology | 13.8 - 17.2 (M) / 12.1 - 15.1 (F) | 14.5 - 16.5 (M) / 13.0 - 14.5 (F) | Semi-Annually (6 Months) | Primary erythrocyte oxygen carrier. Essential for tissue aerobic capacity and mitochondrial ATP production. |
| Red Cell Distribution Width RDW · Hematology | 11.5 - 14.5 | 11.5 - 12.5 | Semi-Annually (6 Months) | Measures erythrocyte size heterogeneity (anisocytosis). High RDW reflects systemic inflammation and ranks heavily in PhenoAge. |
| White Blood Cell Count WBC · Hematology | 4.0 - 11.0 | 4.5 - 6.5 | Semi-Annually (6 Months) | Total circulating leukocyte count. Values persistently above 7.0 x10^3/uL associate with elevated chronic vascular inflammation. |
| Lymphocyte Percentage Lymph % · Hematology | 20.0 - 40.0 | 28.0 - 38.0 | Semi-Annually (6 Months) | Adaptive immune fraction. Progressive age-related lymphopenia indicates immunosenescence and is scored in PhenoAge. |
| Platelet Count PLT · Hematology | 150 - 450 | 175 - 275 | Semi-Annually (6 Months) | Thrombocyte count governing primary hemostasis and vascular repair. Essential input in the FIB-4 liver fibrosis index. |
| 25-Hydroxyvitamin D3 25-OH Vitamin D · Micronutrients | 30 - 100 | 50 - 80 | Semi-Annually (6 Months) | Secosteroid hormone regulating calcium homeostasis, innate immune peptide expression, and genomic transcription. |
| Serum Vitamin B12 (Cobalamin) Vitamin B12 · Micronutrients | 200 - 900 | 500 - 900 | Annually (12 Months) | Essential cofactor for methionine synthase and methylmalonyl-CoA mutase. Critical for DNA synthesis and myelin sheath integrity. |
| Red Blood Cell Magnesium RBC Mg · Micronutrients | 4.2 - 6.8 | 5.8 - 6.8 | Semi-Annually (6 Months) | Intracellular magnesium evaluation. Superior to serum magnesium in reflecting total body stores and enzyme cofactor capacity. |
| Serum Zinc Zinc · Micronutrients | 60 - 130 | 85 - 120 | Annually (12 Months) | Catalytic component of over 300 metalloenzymes including superoxide dismutase and DNA polymerase repair complexes. |
| Triglyceride to HDL-C Ratio TG / HDL-C · Calculated Ratios | < 3.0 | < 1.5 (Optimal Insulin Sensitivity: < 1.0) | Semi-Annually (6 Months) | Powerful surrogate for small dense atherogenic LDL particles and hepatic insulin resistance without costly specialized NMR testing. |
| ApoB to ApoA1 Ratio ApoB / ApoA1 · Calculated Ratios | < 0.80 (M) / < 0.70 (F) | < 0.50 (M) / < 0.40 (F) | Semi-Annually (6 Months) | Atherogenic particle balance. Ratio of pro-atherogenic apoB lipoproteins to protective apoA1 anti-atherogenic lipoproteins. |
| De Ritis Ratio (AST / ALT) AST / ALT · Calculated Ratios | 0.8 - 1.5 | 0.8 - 1.2 | Semi-Annually (6 Months) | Diagnostic ratio differentiating steatosis (AST/ALT < 1.0) from advanced fibrotic remodeling or toxic liver damage (AST/ALT > 2.0). |
| Fibrosis-4 Liver Index FIB-4 · Calculated Ratios | < 1.30 | < 1.00 | Annually (12 Months) | Validated non-invasive liver fibrosis scoring algorithm incorporating age, AST, ALT, and platelet count. |
| BUN to Serum Creatinine Ratio BUN / Cr · Calculated Ratios | 10 - 20 | 12 - 16 | Semi-Annually (6 Months) | Evaluates pre-renal azotemia versus intrinsic parenchymal renal pathology and systemic hydration status. |
