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Reference

What your blood markers actually mean

Physician-reviewed explanations, written against the Indian picture rather than a reference range imported from somewhere else.

A biomarker is a measurable signal in blood or urine that says something about how your body is working. The Peak Brain panel measures 130 of them across 7 groups, and the value is not in the count — it is in reading them together. A lipid result means something different beside a raised inflammatory marker than it does alone; a normal ferritin means something different when hs-CRP is high. This reference explains 12 of the markers individually: what each one measures, what a high or low result indicates, the ranges laboratories use, and the other markers it has to be interpreted alongside. Where the Indian picture departs from the Western default — and for insulin resistance, lipoprotein(a), B12 and vitamin D it departs substantially — each page says so.

01

Browse by group

Each group collects markers that are physiologically related and therefore read as a set. Start with the group that matches what you are trying to understand.

02

Energy & metabolic

All energy & metabolic markers

Glucose, insulin and the full lipid picture: the pattern behind afternoon crashes, years before it reads as diabetes risk.

Fasting insulin

Fasting insulin measures how much insulin the pancreas is releasing to hold blood glucose steady after an overnight fast.

HOMA-IR

HOMA-IR is a calculated index that combines fasting glucose and fasting insulin into a single number describing how resistant the body has become to its own insulin.

HbA1c

HbA1c measures the proportion of haemoglobin in your red blood cells that has sugar attached to it.

03

Hormones & thyroid

All hormones & thyroid markers

Thyroid, cortisol rhythm and sex hormones, tuned to how you actually move through a day, not just to a reference range.

TSH

TSH is the signal the pituitary gland sends to instruct the thyroid to produce hormone, and it moves in the opposite direction to thyroid output.

04

Cognitive load & stress

All cognitive load & stress markers

The inflammatory, methylation and micronutrient signals that sit underneath brain fog and a short fuse.

hs-CRP

hs-CRP is a high-sensitivity measurement of C-reactive protein, a substance the liver releases in response to inflammation.

Homocysteine

Homocysteine is an amino acid produced continuously as the body processes methionine from dietary protein.

Omega-3 index

The omega-3 index measures EPA and DHA — the two long-chain omega-3 fatty acids — as a percentage of the total fatty acids in red blood cell membranes.

05

Nutrients & electrolytes

All nutrients & electrolytes markers

India's most common and most overlooked gaps: the ones that quietly cost you hours of clarity everyday.

Ferritin

Ferritin is the protein the body uses to store iron, and the amount circulating in blood is proportional to how much iron is held in reserve.

Vitamin D (25-OH)

Vitamin D is measured as 25-hydroxyvitamin D, the circulating storage form, which reflects combined intake from sunlight, diet and supplements over the preceding weeks.

Vitamin B12

Vitamin B12 is required for red blood cell formation, DNA synthesis and the maintenance of the myelin sheath around nerves.

06

Heart & long-term risk

All heart & long-term risk markers

The markers a routine checkup usually skips, and the ones that decide your next thirty years.

ApoB

ApoB, or apolipoprotein B, is a protein that sits on the surface of every cholesterol particle capable of lodging in an artery wall.

Lp(a)

Lp(a), pronounced "L-P-little-a", is a cholesterol-carrying particle whose blood concentration is set almost entirely by the genes you inherited.

Questions about biomarkers

What is a biomarker?

A biomarker is any measurable characteristic of the body that indicates something about health or disease. In blood work it means the individual substances a laboratory measures — glucose, ferritin, ApoB, TSH and so on. Each is a single data point; the clinical value comes from reading them together.

Why does one marker need to be read alongside others?

Because most markers are ambiguous alone. A normal ferritin can conceal iron deficiency if inflammation is raised. A normal HbA1c can coexist with substantial insulin resistance. A normal TSH does not rule out thyroid dysfunction. The pattern across markers carries the information that any single value cannot.

Are Western reference ranges valid for Indian patients?

Often not directly. Indians develop insulin resistance at lower body weights, carry higher average lipoprotein(a), and have widespread B12 and vitamin D deficiency — so ranges derived from European-ancestry cohorts can describe an Indian result as unremarkable when it is not. Each page here notes where the Indian picture differs.

Does a result inside the reference range mean I am healthy?

Not necessarily. A reference range describes the middle 95% of a reference population, not a state of health. Where the underlying population has a high prevalence of the abnormality — as with dyslipidaemia in India at 81.2% — being inside the range is weaker reassurance than it sounds.

The programme

One marker rarely answers the question.

Peak Brain draws a full blood and urine panel at your home, has a licensed physician read every marker together rather than one at a time, and turns what they find into a ranked 90-day protocol with a retest at the end.

How the programme works