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Blood test reference ranges
Look up the usual adult reference range for common blood tests — haemoglobin, ferritin, vitamin D, HbA1c, cholesterol, TSH, and more — in SI and conventional units, in plain language. The checker runs entirely in your browser; nothing is uploaded.
General information only — not a diagnosis, not treatment and not a substitute for your doctor. Reference ranges differ between laboratories, so the range printed on your own report is the one that counts, and only a clinician who knows your history can say what a result means for you. Never start, stop or change a medicine or supplement based on this page.
Check a value against the usual range
Pick a marker, type your result and its unit, and the page tells you whether it sits inside the typical adult reference interval. This is a rough orientation only — your own lab's range, and your doctor's reading of it, are what count. Nothing you enter leaves your browser.
Reference-range checker
JavaScript is off. Every marker below links to its own page with the full reference range, computed and written out on the server.
The checker compares against a typical adult reference interval in the unit shown. It is not a diagnosis. A value inside the range does not rule anything out, and a value outside it does not rule anything in.
Every marker and its typical range
Full blood count
| Marker | Also called | Typical adult range |
|---|---|---|
| Haemoglobin | Hb, HGB | 120–170 g/L |
Iron studies
| Marker | Also called | Typical adult range |
|---|---|---|
| Ferritin | Serum ferritin | 15–300 µg/L |
Vitamins
| Marker | Also called | Typical adult range |
|---|---|---|
| Vitamin D (25-OH) | 25-hydroxyvitamin D, calcidiol | 50–250 nmol/L |
| Vitamin B12 | Cobalamin | 148–650 pmol/L |
| Folate | Serum folate, vitamin B9 | 7 nmol/L or above |
Glucose
| Marker | Also called | Typical adult range |
|---|---|---|
| HbA1c | Glycated haemoglobin, A1c | below 42 mmol/mol |
| Fasting glucose | Fasting plasma glucose, FPG | 3.9–5.5 mmol/L |
Lipids
| Marker | Also called | Typical adult range |
|---|---|---|
| Total cholesterol | TC | below 5 mmol/L |
| LDL cholesterol | LDL-C, "bad" cholesterol | below 3 mmol/L |
| HDL cholesterol | HDL-C, "good" cholesterol | 1 mmol/L or above |
| Triglycerides | TG | below 1.7 mmol/L |
Thyroid
| Marker | Also called | Typical adult range |
|---|---|---|
| TSH | Thyroid-stimulating hormone, thyrotropin | 0.4–4 mIU/L |
Inflammation
| Marker | Also called | Typical adult range |
|---|---|---|
| CRP | C-reactive protein | below 5 mg/L |
Liver
| Marker | Also called | Typical adult range |
|---|---|---|
| ALT | Alanine aminotransferase, ALAT, SGPT | below 41 U/L |
Kidney
| Marker | Also called | Typical adult range |
|---|---|---|
| Creatinine | Serum creatinine | 44–106 µmol/L |
| eGFR | Estimated glomerular filtration rate | 60 mL/min/1.73m² or above |
Electrolytes
| Marker | Also called | Typical adult range |
|---|---|---|
| Sodium | Na, serum sodium | 135–145 mmol/L |
| Potassium | K, serum potassium | 3.5–5.1 mmol/L |
Source: Typical adult reference intervals published by clinical laboratories; intervals differ by laboratory, method and population · checked 2026-09-02
How to read a reference range
A reference range is not a boundary between healthy and sick. It is built by measuring a large group of people assumed to be healthy and reporting the middle 95% of their results, which means that, by construction, one healthy person in twenty falls outside it. A result a little outside the range is therefore common and frequently means nothing at all.
The direction and size of a change matter more than a single crossing of a line, and a result is read alongside your symptoms, your history, your medicines and your other tests. This is exactly why a number cannot be self-interpreted from a table: the same figure can be reassuring in one person and worth investigating in another.
Frequently asked questions
Is my data uploaded anywhere?
No. The checker on this page runs entirely in your browser. Nothing you type is sent to a server, saved to an account or logged. Close the tab and it is gone.
Why does my lab use a different range?
Reference ranges are set by each laboratory from the population and the analyser it uses, so they legitimately differ. That is why the range on this page is described as typical, and why the number on your own report is the one to compare against.
My result is outside the range — is something wrong?
Not necessarily. A result just outside a reference interval is common and often means nothing; reference intervals are defined so that a fraction of perfectly healthy people fall outside them by definition. A result only has meaning in the context of your symptoms, your history and your other results — which is your doctor's job, not a web page's.
Can this diagnose a condition?
No. This is reference information, not a diagnosis. A single number cannot diagnose anything; interpretation needs a clinician.
What is the difference between SI and conventional units?
They are two measurement systems for the same quantity. Most of the world reports blood tests in SI units (for example mmol/L); the United States often uses conventional units (for example mg/dL). Each marker page shows both where they differ so you can read either report.
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