BUN
Blood urea nitrogen (BUN) measures the amount of urea nitrogen in your blood. Urea nitrogen is a waste product created when your body breaks down protein, and your kidneys filter it out.
Category: Metabolic Panel
Also known as: bun, blood urea nitrogen, urea nitrogen, urea, ureja
Reference range: 7–20 mg/dL (Source: ABIM)
Standard unit: mg/dL
High values may indicate
High BUN levels may indicate kidney disease, dehydration, a high-protein diet, heart failure, or urinary tract obstruction.
Low values may indicate
Low BUN levels may indicate liver disease, malnutrition, overhydration, or a very low-protein diet.
Frequently asked questions
- What is a normal BUN level?
- A typical reference range for BUN is 7–20 mg/dL (source: ABIM). Reference ranges vary by laboratory, age, and sex, so always compare against the range on your own lab report.
- What units is BUN measured in?
- BUN is most commonly reported in mg/dL. Labs in different countries may use other units — you can convert between them with BloodId's blood test unit converter.
- Where do BUN reference ranges come from?
- BloodId uses ABIM standard reference ranges and educational information from MedlinePlus (see our methodology). Reference ranges still vary by lab, age, and sex, so always compare against your own report.
- Can I track BUN over time?
- Yes. Upload results from any lab and BloodId charts your BUN over time against its reference range, so you can see whether the trend is rising, falling, or stable.