Longevity & Aging
measuring biological vs chronological age.

DNA methylation clocks calculate biological age from epigenetic marks on hundreds of CpG sites; the most validated measure of aging pace.

Telomeres cap chromosomes and shorten with each cell division; length reflects replicative history and cumulative oxidative stress.

Insulin-like growth factor-1 mediates growth hormone's effects on muscle, bone, and organ repair; a key longevity axis marker.

GlycanAge measures the glycosylation pattern of IgG antibodies, a highly sensitive molecular clock of biological aging and immune fitness.

APOE encodes apolipoprotein E, which regulates lipid transport and brain amyloid clearance; the ε4 allele elevates Alzheimer's risk.

Total count of white blood cells; the front-line defense of the immune system.

Total red blood cell count; used alongside hemoglobin and hematocrit to assess anemia.

The oxygen-carrying protein in red blood cells; the primary measure of anemia severity.

The fraction of blood volume occupied by red blood cells.

Mean corpuscular volume — the average size of red blood cells; elevated in B12/folate deficiency, low in iron deficiency.

Mean corpuscular hemoglobin — the average amount of hemoglobin per red cell; low MCH is an early signal of iron depletion.

Mean corpuscular hemoglobin concentration — classic for iron-deficiency anemia when low.

Red cell distribution width — measures variability in red cell size; elevated RDW reflects oxidative stress and mixed deficiencies.

The circulating particles that initiate clotting; low counts increase bleeding risk, high counts can reflect inflammation or iron deficiency.

Mean platelet volume — larger platelets are more reactive; elevated MPV is associated with cardiovascular and thrombotic risk.

Absolute count of neutrophils — the first responders to bacterial infection.

Immature neutrophils (bands) — elevated counts (left shift) indicate acute bacterial infection or bone marrow stress.

Immature granulocyte precursors; presence in blood indicates bone marrow stress or severe infection.

Granulocyte precursors; circulating myelocytes indicate abnormal bone marrow release.

Very early granulocyte precursors; their presence in blood is abnormal and requires urgent evaluation.

Absolute count of lymphocytes — key mediators of adaptive immunity including T and B cells.

Absolute monocytes; these differentiate into macrophages and dendritic cells in tissue.

Absolute eosinophils; respond to allergic reactions and parasitic infections.

Absolute basophils — the rarest white cell, involved in allergic and inflammatory responses.

Blast cells in peripheral blood; any presence is abnormal and requires immediate haematology referral.

Nucleated red blood cells in peripheral blood; normally only present in foetal circulation and severe anaemia.

Percentage of neutrophils in the white cell differential; elevated in bacterial infection and stress.

Percentage of band (immature) neutrophils; elevated in acute bacterial infection.

Percentage of metamyelocytes; should be absent from normal peripheral blood.

Percentage of myelocytes; absent from normal blood.

Percentage of promyelocytes; absent from normal blood.

Percentage of lymphocytes in the white cell differential; reflects adaptive immunity.

Atypical (reactive) lymphocytes; elevated in viral infections such as EBV and CMV.

Percentage of monocytes; elevated in chronic infections and inflammatory conditions.

Percentage of eosinophils; elevated in allergic and parasitic conditions.

Percentage of basophils; mildly elevated counts can accompany allergic inflammation or thyroid disease.

Percentage of blasts; absent from normal blood. Any presence requires urgent evaluation.

Nucleated RBCs per 100 WBCs; should be absent in normal adults.

Pathologist or automated comment on peripheral blood findings.

Fasting serum glucose — the primary screen for diabetes and metabolic dysfunction.

Blood urea nitrogen — a kidney filtration marker; elevated with dehydration or renal impairment.

Muscle waste product filtered by the kidneys; used to estimate GFR.

Estimated glomerular filtration rate — the best single-number indicator of kidney function, calculated from creatinine using CKD-EPI.

The ratio of BUN to creatinine; helps distinguish pre-renal from intrinsic kidney causes of elevated BUN.

Primary extracellular cation; regulates fluid balance and nerve/muscle function.

Primary intracellular cation; critical for heart rhythm, muscle contraction, and nerve signalling.

The main anion that balances sodium; used to evaluate acid-base and electrolyte status.

Serum bicarbonate reflecting the body's acid-base reserve; low values can indicate metabolic acidosis.

Total serum calcium; critical for bone density, muscle contraction, and nerve signalling.

Total serum protein (albumin + globulins); reflects overall nutritional status and liver and immune function.

The most abundant serum protein; reflects liver synthetic function, nutrition, and systemic inflammation.

Calculated globulin fraction (total protein minus albumin); includes immunoglobulins, clotting factors, and transport proteins.

The A/G ratio; a low ratio (reversed) can indicate autoimmune disease, liver disease, or malignancy.

The breakdown product of haemoglobin; elevated in liver disease, haemolysis, or bile duct obstruction.

Enzyme produced in liver and bone; elevated in cholestasis, bone disease, and pregnancy.

Aspartate aminotransferase — liver and muscle enzyme; elevated with hepatocellular damage or intense exercise.

Alanine aminotransferase — the most specific liver enzyme; elevated in hepatitis, fatty liver, and medication toxicity.

High-sensitivity C-reactive protein — the most sensitive blood measure of systemic low-grade inflammation.