BUN

Medical Abbreviation
BUN

BUN stands for Blood Urea Nitrogen.

What does BUN mean?

a blood test that reflects kidney function

BUN stands for blood urea nitrogen, a measure of the amount of nitrogen in the blood that comes from urea, a waste product made by the liver and removed by the kidneys. A BUN test helps assess kidney function and hydration. A high BUN can point to reduced kidney function, dehydration, or a high protein load, while a low BUN is less common. It is often interpreted alongside creatinine, and the BUN to creatinine ratio can help find the cause of a problem.

When is BUN used?

BUN is a standard part of basic metabolic panels in primary care, emergency, and hospital settings.

Frequently asked questions

What does BUN stand for?

BUN stands for blood urea nitrogen, a blood test that reflects kidney function.

What does a high BUN mean?

A high BUN can indicate reduced kidney function, dehydration, or a high protein load.

Why is BUN measured with creatinine?

The BUN to creatinine ratio helps identify the cause of a kidney or hydration problem.

Is BUN part of routine blood tests?

Yes. It is a standard part of the basic metabolic panel ordered in many settings.

Related abbreviations

CKD · AKI · CBC

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Study reference only — not medical advice. Always consult qualified sources and supervisors for clinical decisions.