Normal is not the same as optimal.
A lab reference range describes the middle 95% of the people the lab sampled. It answers one question — do you look like most people? — and it answers it well. It was never designed to answer the question you are actually asking, which is where in that range people go on to stay healthy the longest. Every marker here shows both ranges side by side, with the reasoning and the source for each.
How to read these pages
Optimal ranges come mostly from large observational studies, so they are targets rather than verdicts. Being outside one is a reason to look closer, not a diagnosis — and moving a number is not the same as changing an outcome. Read the trend across several tests rather than any single reading, and look at what was going on the week the blood was drawn. Nothing here replaces a conversation with a doctor who can see your whole picture.
Cardiovascular
ApoB
The number of atherogenic lipoprotein particles in circulation — one ApoB molecule sits on every LDL, VLDL, IDL and Lp(a) particle, so ApoB is a direct particle count.
- Lab normal
- 55–140 mg/dL
- Optimal
- < 80 mg/dL
Lp(a)
An LDL-like particle carrying an additional apolipoprotein(a) tail. Blood level is roughly 90% genetically determined and stable across life.
- Lab normal
- < 75 nmol/L
- Optimal
- < 75 nmol/L
LDL cholesterol
The mass of cholesterol carried inside LDL particles — usually calculated from total cholesterol, HDL and triglycerides rather than measured directly.
- Lab normal
- < 100 mg/dL
- Optimal
- < 70 mg/dL
HDL cholesterol
Cholesterol carried on high-density lipoprotein particles, involved in reverse cholesterol transport.
- Lab normal
- 40–60 mg/dL
- Optimal
- 50–80 mg/dL
Homocysteine
A sulphur-containing amino acid produced in methionine metabolism, cleared by pathways requiring folate, B12 and B6.
- Lab normal
- 5–15 µmol/L
- Optimal
- 5–9 µmol/L
Metabolic
Triglycerides
Circulating fat available for energy or storage, carried mainly on VLDL particles.
- Lab normal
- < 150 mg/dL
- Optimal
- < 80 mg/dL
HbA1c
The proportion of haemoglobin that has become glycated — a weighted average of blood glucose over the preceding 8–12 weeks.
- Lab normal
- < 5.7 %
- Optimal
- 4.8–5.4 %
Fasting glucose
Blood glucose after 8 or more hours without food.
- Lab normal
- 70–99 mg/dL
- Optimal
- 75–86 mg/dL
Fasting insulin
How much insulin the pancreas is secreting to hold fasting glucose where it is.
- Lab normal
- 2–25 µIU/mL
- Optimal
- 2–6 µIU/mL
HOMA-IR
A calculated index of insulin resistance: fasting glucose (mg/dL) × fasting insulin (µIU/mL) ÷ 405. In mmol/L units the divisor is 22.5.
- Lab normal
- < 2.9 index
- Optimal
- < 1.5 index
Uric acid
The end product of purine metabolism, cleared mainly by the kidneys.
- Lab normal
- 3.5–7.2 mg/dL
- Optimal
- 3.5–5.5 mg/dL
Inflammation
RDW
How much red blood cells vary in size. A low value means a uniform population; a high one means the marrow is producing cells of inconsistent size.
- Lab normal
- 11.5–14.5 %
- Optimal
- 11.5–13 %
hs-CRP
An acute-phase protein made by the liver, measured with a high-sensitivity assay able to resolve the low range where cardiovascular risk stratification happens.
- Lab normal
- < 3 mg/L
- Optimal
- < 1 mg/L
Hormonal
IGF-1
The hormone through which most of growth hormone's effects are actually delivered. Because it is stable across the day where growth hormone is pulsatile, IGF-1 is the practical way to read GH status from a single blood draw.
- Lab normal
- 80–250 ng/mL
- Optimal
- 120–160 ng/mL
Testosterone (total)
Total circulating testosterone, most of which is bound to SHBG and albumin and therefore unavailable to tissue. Ranges here are for men; female physiology sits an order of magnitude lower and needs different interpretation entirely.
- Lab normal
- 300–1000 ng/dL
- Optimal
- 500–800 ng/dL
TSH
The pituitary's signal telling the thyroid to produce more hormone. It moves inversely to thyroid output, so a high TSH means an underactive thyroid.
- Lab normal
- 0.45–4.5 mIU/L
- Optimal
- 1–2 mIU/L
Organ function
eGFR
How fast the kidneys filter blood, estimated from serum creatinine together with age and sex. It is a calculation, not a measurement.
- Lab normal
- > 90 mL/min/1.73m²
- Optimal
- > 90 mL/min/1.73m²
Albumin
The most abundant protein in blood, made by the liver. It maintains oncotic pressure and carries hormones, drugs and fatty acids.
- Lab normal
- 3.5–5 g/dL
- Optimal
- 4.3–5 g/dL
GGT
A liver enzyme involved in glutathione metabolism, released with hepatobiliary stress or enzyme induction.
- Lab normal
- < 50 U/L
- Optimal
- < 20 U/L
ALT
An enzyme concentrated in liver cells, released into blood when they are stressed or damaged.
- Lab normal
- < 40 U/L
- Optimal
- < 25 U/L
Nutrient status
Vitamin D (25-OH)
The circulating storage form of vitamin D, and the standard index of vitamin D status.
- Lab normal
- 30–100 ng/mL
- Optimal
- 40–60 ng/mL
Ferritin
The body's iron storage protein, and the best single indicator of total iron stores — but also an acute-phase reactant.
- Lab normal
- 30–400 ng/mL
- Optimal
- 50–150 ng/mL
Vitamin B12
Circulating cobalamin, most of which is bound to proteins that do not deliver it to tissues.
- Lab normal
- 200–900 pg/mL
- Optimal
- 500–900 pg/mL
Magnesium (RBC)
Magnesium inside red blood cells, which reflects tissue stores far better than the serum magnesium usually included on a routine panel.
- Lab normal
- 4.2–6.8 mg/dL
- Optimal
- 5.6–6.8 mg/dL
Reading about a marker changes nothing on its own. Log your latest results and the site tracks each one against both ranges — then retest on the schedule the marker needs, and watch the direction of travel.