Biomarkers

Stored iron. Can be at the floor while your blood count reads perfectly normal.

Circulating iron and how much capacity is left to carry it.

The oxygen carrier itself, and the last thing your body lets fall.

On every blood count, read least often, and the size may matter as much as the number.

The pituitary's instruction to the thyroid, and why the range is argued over.

The active hormone actually doing the work in your tissues.

The storage hormone waiting to be converted.

Autoimmune activity that can run for years while TSH still reads normal.

The second antibody, and occasionally the only one that turns positive.

Real physiology, and a test that cannot do the job it is sold for.

How hard your body is working to hold blood sugar steady.

Your average blood sugar over about three months.

The standard screen, and one of the last numbers to move.

A cheap and telling read on metabolic health, calculable free.

Known for gout, and quietly a metabolic marker on a standard panel.

Low-grade systemic inflammation, and the number that tells you whether to trust a high ferritin.

A methylation and B-vitamin marker, with a cardiovascular story that did not hold up.

A clotting protein and an inflammation marker, with 154,211 people behind it.

Counts the atherogenic particles rather than the cholesterol inside them.

Largely genetic, measured once in a lifetime, and almost never ordered.

What is in your cell membranes, rather than what the label claims.

The marker whose official threshold was withdrawn in 2024, and what that means.

Can sit inside the reference range while symptoms are already present.

Half of a pair, and the half people correct without checking the other.

One of the few vitamins where too much causes the same nerve damage as too little.

Widely inadequate from food, and a meta-analysis found harm at high doses.

Two forms, two jobs, and no gold-standard status test.

Why the standard serum magnesium test tells you very little.

A validated test with known sensitivities, and no standard panel runs it.

The mineral zinc quietly displaces, measured by two tests that can disagree.

Built into the enzymes that activate thyroid hormone, with a close ceiling.

Essential for thyroid hormone, and close to unmeasurable from one sample.

A total number that means little without knowing how much is available.

Uninterpretable without a cycle day attached, and readable after menopause.

One point on a curve that moves more in a day than most hormones move in a lifetime.

Declines steadily with age, and gets read against the wrong range constantly.

On every standard panel, and normal may describe a population that is not well.

The liver enzyme most sensitive to alcohol, and a read on oxidative stress.

Sold as a nutrition marker, and mostly reporting on inflammation instead.

An estimate rather than a measurement, and the equation changed in 2021.