Why is Urea Nitrogen (Bun) important?

BUN measures urea nitrogen, a waste product formed when the liver breaks down proteins. In functional medicine, BUN primarily reflects kidney function, as healthy kidneys filter and excrete urea efficiently. Elevated BUN may indicate decreased kidney function, dehydration, high protein intake, or certain medications. Low BUN may suggest liver disease, malnutrition, or overhydration. The BUN-to-creatinine ratio provides additional insight: high ratios may indicate dehydration or upper GI bleeding, while low ratios may suggest liver disease or low protein intake. BUN is less specific than creatinine for kidney function but provides valuable complementary information.

What are the symptoms of abnormal Urea Nitrogen (Bun) levels?

High BUN: fatigue, nausea, confusion, decreased urination (if kidney-related). Low BUN: often asymptomatic but may indicate underlying liver or nutritional issues.

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Urea Nitrogen (Bun)

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BUN reflects kidney filtration capacity and protein metabolism. Optimal levels indicate healthy kidney function and appropriate protein processing by the liver.

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BUN measures urea nitrogen, a waste product formed when the liver breaks down proteins
In functional medicine, BUN primarily reflects kidney function, as healthy kidneys filter and excrete urea efficiently
Elevated BUN may indicate decreased kidney function, dehydration, high protein intake, or certain medications
Low BUN may suggest liver disease, malnutrition, or overhydration
The BUN-to-creatinine ratio provides additional insight: high ratios may indicate dehydration or upper GI bleeding, while low ratios may suggest liver disease or low protein intake
BUN is less specific than creatinine for kidney function but provides valuable complementary information

BUN reflects kidney filtration capacity and protein metabolism
Optimal levels indicate healthy kidney function and appropriate protein processing by the liver

High BUN: fatigue, nausea, confusion, decreased urination (if kidney-related).
Low BUN: often asymptomatic but may indicate underlying liver or nutritional issues.

High BUN: kidney disease, dehydration, high protein diet, certain medications, heart failure, GI bleeding.
Low BUN: liver disease, malnutrition, overhydration, pregnancy, very low protein diet.

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Urea Nitrogen (Bun)

About Urea Nitrogen (Bun)

Why Urea Nitrogen (Bun) Matters

Symptoms of Urea Nitrogen (Bun)

What Affects Urea Nitrogen (Bun) Levels

How it works: 4 easy steps

Choose your tests

Quick & convenient testing

Clear, personalized results

Optimize your health

Our Comprehensive Panels

Explore Other Tests

Basophils

Apolipoprotein B

Nitrite

Monocyte-to-Lymphocyte Ratio (MLR)

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