Blood nitrogen waste marker
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About BUN
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About BUN
Overview and History
BUN is a quantitative blood analyte that reports the concentration of nitrogen in circulating urea. Urea is produced in the liver from ammonia generated during protein catabolism and is removed primarily by glomerular filtration; labs typically report BUN in mg/dL as a routine marker of nitrogen balance and excretory load.
BUN has been used for decades in clinical chemistry to track changes in protein metabolism, hydration status, and renal clearance. It is non-specific alone, so clinicians interpret BUN together with creatinine, electrolytes, and metabolic markers to identify physiologic patterns relevant to cardiovascular assessment.
Interpreting Highs and Lows
Elevated BUN may be associated with reduced renal clearance, lower plasma volume (concentration from dehydration), increased protein breakdown, or higher protein intake; it can also rise with increased nitrogen load from other sources. Low BUN may reflect expanded plasma volume (dilution), low dietary protein intake, or reduced hepatic urea synthesis. Because many factors influence BUN, results are interpreted alongside creatinine, fluid indicators, metabolic markers, medications, and genetic data to form a complete clinical picture.
Featured Test
BUN is included in Cardio Zoomer to evaluate nitrogen handling and renal excretory patterns that affect fluid balance, metabolic strain, and vascular load. When combined with creatinine, electrolytes, metabolic markers, and genetic data, BUN helps clarify whether cardiovascular signals are related to volume shifts, protein turnover, or impaired clearance, supporting more precise interpretation of patient risk.
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Mary Beth Augustine
DCN, RDN, FAND- Lead Clinical Educator
Suzanne Barker
MS, RDN, LD, CTTS, CGP- Clinical Educator
Suzette Garcia
MSc- MHNE- Clinical Educator
Brooke Mader Ganev
MS, CNS, LDN, FDN- Clinical Educator
Adair Anderson
MS, RDN, LDN- Clinical Educator
Lillie Luu Nguyen
DCN, CNS, LDN- Clinical Educator
Jason Barker
ND- Clinical Educator
Emaline Brown
ND- Clinical Educator
Dana Filatova
DCN, CNS, LDN- Clinical Educator
Jessy Dhanjal
ND- Clinical Educator
Nour Amri
MS, LDN, CNS, CKNS- Clinical Educator
