Kidney system

Blood Urea Nitrogen (BUN)

BUN

A waste product cleared by the kidneys — used alongside creatinine.

What is it

Blood Urea Nitrogen (BUN) — in plain English.

Blood urea nitrogen reflects the body's protein metabolism waste cleared by the kidneys. Levels can be influenced by hydration, diet, and kidney function.

Why it's measured

What BUN can reveal.

BUN has been used alongside creatinine to evaluate kidney function and hydration status in research and clinical practice.

Reference range

Where most laboratories draw the standard line.

Standard laboratory reference

7 – 20 mg/dL

Reference ranges vary by laboratory. Your individual reference range will appear on your test report and should be interpreted by your physician in the context of your overall health profile.

Where does your number land?

Drag to your own Blood Urea Nitrogen (BUN) result.

Educational only, not a diagnosis. Ranges vary by laboratory. See which panel includes Blood Urea Nitrogen (BUN).

What results may indicate

Higher vs. lower BUN — at a high level.

Elevated

Has been associated with dehydration, reduced kidney function, or high protein intake in research literature.

Lower

May reflect low protein intake or overhydration.

These associations are general. They are not a personal diagnosis or prediction. Discuss your individual results with your physician in the context of your full health profile.

When it's measured

When BUN is typically run.

Part of standard metabolic panels.

Related markers

Often measured alongside BUN.

Common questions

Questions people ask about Blood Urea Nitrogen (BUN)

What is Blood Urea Nitrogen (BUN)?

Blood urea nitrogen reflects the body's protein metabolism waste cleared by the kidneys. Levels can be influenced by hydration, diet, and kidney function.

Why is Blood Urea Nitrogen (BUN) measured?

It's one of the markers used to build a fuller picture of your health. On its own it tells you very little, so it's most informative when reviewed alongside related markers.

How is Blood Urea Nitrogen (BUN) tested?

It's measured from a standard blood draw at Quest or LabCorp. Blood Urea Nitrogen (BUN) is one of the markers included in the OPTML Apex Panel, where your results are read across systems and reviewed by a U.S.-licensed physician.

What should I do with my Blood Urea Nitrogen (BUN) result?

Reference ranges vary by laboratory, and a single value rarely tells the whole story. Review your result with a physician in the context of your other markers, symptoms, and history.

Not sure which panel is right for you?

Blood Urea Nitrogen (BUN) is one signal among many. Answer a few quick questions and we’ll point you to the panel that fits.

Measured in

BUN is one of 160 biomarkers in the Apex Panel.

A complete look at your heart, hormones, metabolism, inflammation, and longevity systems — drawn at Quest or LabCorp, reviewed by a U.S.-licensed physician.

Find the right panel
160 biomarkers13 body systemsPhysician-reviewed
Back to all biomarkers

This information is for general educational purposes only and is not medical advice. Lab results alone are not intended to diagnose, treat, or cure any condition and do not replace the advice of a healthcare provider. OPTML does not offer medical advice, a diagnosis, medical treatment, or any form of medical opinion.

Weight-loss medication disclaimer

OPTML offers compounded semaglutide and tirzepatide, prescribed and overseen by U.S.-licensed physicians. Compounded drug products are not approved or evaluated for safety, effectiveness, or quality by the FDA. OPTML is not associated with, endorsed by, or affiliated with the manufacturers of FDA-approved branded weight-loss medications, and does not sell or supply those branded products. Anyone interested in an FDA-approved branded medication should consult a licensed healthcare provider or pharmacist. Individual results vary; no specific result is promised, and weight management requires ongoing medical guidance.

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