Lever
Lifestyle
- Maintain adequate hydration
- Regular exercise
- Monitor protein intake
Blutwerte · Marker
Harnstoff
BUN · Blood Urea Nitrogen · Urea · Harnstoff-N
Nierenwerte
- Einheit:
- mmol/L
- Abbreviation
- BUN / Urea
Blood urea nitrogen (BUN) measures the concentration of urea in the blood, reflecting protein metabolism and renal function.
Reference Ranges
Reference
2.5–7.5mmol/L
2.5
3
6
7.5
LowNormalHigh
Reference
Optimal
Unit · mmol/LReference ranges may vary slightly based on laboratory standards and patient demographics.
Overview
Übersicht
Urea, also known as blood urea nitrogen (BUN), is a waste product formed in the liver through the urea cycle, where ammonia is converted into urea. This process is crucial for the detoxification of ammonia, a byproduct of protein metabolism. Urea is then transported in the blood to the kidneys, where it is excreted in urine. Researchers have long used BUN as a marker for assessing renal function, as it reflects the kidney's ability to filter waste products from the blood. Elevated BUN levels can indicate impaired kidney function or other conditions affecting the urea cycle. Clinically, BUN is an important marker for diagnosing and monitoring renal diseases, such as acute kidney injury and chronic kidney disease. It is also used to evaluate the severity of conditions like severe acute pancreatitis, where elevated levels may predict complications and mortality. In the context of athletic performance and biohacking, BUN levels can provide insights into protein metabolism and hydration status. Athletes and biohackers may monitor BUN to optimize protein intake and kidney health. However, BUN levels can be influenced by factors such as diet, hydration, and muscle mass, which may confound results. Therefore, it is important to consider these factors when interpreting BUN levels, and fasting or standardized testing conditions may be recommended to reduce variability.
Klinische Bedeutung
Elevated BUN levels may indicate renal dysfunction, dehydration, or increased protein catabolism. Low BUN levels can suggest liver dysfunction or malnutrition.
Dynamics
Trend Interpretation
Rising Values
Progressively rising BUN levels suggest worsening renal function or dehydration. Retest in 4 weeks if levels are outside the optimal range.
Falling Values
Progressively falling BUN levels may indicate improved hydration or dietary changes.
Re-test Interval
4 weeks if outside optimal range
Etiology
Causes — High & Low
Cause
Elevated Levels
- Renal dysfunction
- Dehydration
- High protein diet
- Heart failure
- Gastrointestinal bleeding
Cause
Low Levels
- Liver failure
- Malnutrition
- Overhydration
- Low protein diet
- Pregnancy
Protocol
How to Optimize
Lever
Nutrition
- Balanced protein consumption
- Increase water intake
- Limit excessive protein supplements
Note:
Consult a healthcare provider before making significant dietary or lifestyle changes, especially if kidney function is impaired.
Testing Guidelines
✓Fasting Not Required
✓Not Time-Sensitive
BUN levels can vary throughout the day; testing at the same time is recommended for consistency.
Testing Frequency
Annually for healthy adults, more frequently if monitoring kidney function.
Interfering Factors
- High protein intake
- Dehydration
- Recent intense exercise
Related Peptides & Hormones
Creatinine
hormone or peptideCorrelated with
Open Research Questions
Current research suggests that reference ranges and optimal targets for blood urea nitrogen (BUN) remain debated, particularly in the context of acute kidney injury and severe acute pancreatitis, where confounding factors may affect its predictive value. Emerging research directions include the identification of novel urinary biomarkers for renal injury and the development of non-invasive ammonia detection methods. However, clinical questions regarding the sensitivity and specificity of these biomarkers in diverse populations remain unanswered.
53 Research Publications
693
Total Citations
29
Human/RCT
2.6
Avg. Influence
2026
Latest
Sort
Filter
01Top
#01
Emergence of blood urea nitrogen as a biomarker of neurohormonal activation in heart failure.
ReviewInfluence8.0
223
This study highlighted blood urea nitrogen (BUN) as a potential biomarker for neurohormonal activation in heart failure. Researchers noted that BUN levels could indicate renal response to neurohormonal changes, suggesting its relevance in heart failure management.
02Top
#02
Curcumin ameliorates cadmium-induced nephrotoxicity in Sprague-Dawley rats.
AnimalInfluence4.0
103
03Top
#03
Association of vancomycin plus piperacillin-tazobactam with early changes in creatinine versus cystatin C in critically ill adults: a prospective cohort study.
HumanInfluence3.0
83
Researchers observed that vancomycin combined with piperacillin-tazobactam increased creatinine levels but did not significantly affect blood urea nitrogen (BUN) or other kidney biomarkers. This suggests that changes in creatinine may represent pseudotoxicity rather than true kidney injury.
04
#04
Blood urea nitrogen and creatinine.
HumanInfluence5.0
68
This study examined the relationship between serum creatinine and blood urea nitrogen (BUN) levels in assessing kidney function. Researchers found that while both markers are useful, serum creatinine is less influenced by external factors and provides a more accurate evaluation of renal health.
05
#05
Identification of Novel Biomarker for Early Detection of Diabetic Nephropathy.
UnknownInfluence2.0
36
Researchers found that diabetic nephropathy (DN) in rats was associated with increased blood urea nitrogen (BUN) and serum creatinine levels, indicating kidney injury. The study identified novel biomarkers that could aid in the early detection of DN.
06
#06
Renal changes and acute kidney injury in covid-19: a systematic review.
Review
34
Researchers conducted a systematic review on renal changes in COVID-19 patients. The review found that increased blood urea nitrogen (BUN) levels were common in patients with acute kidney injury (AKI), indicating significant renal impact from the virus.
07
#07
Blood Urea Nitrogen as a Prognostic Marker in Severe Acute Pancreatitis.
HumanInfluence2.0
20
Researchers found that blood urea nitrogen (BUN) levels were significantly higher in patients with severe acute pancreatitis who did not survive compared to those who did. The study indicated that BUN could serve as an independent risk factor for mortality, with a specific cutoff value predicting 30-day all-cause mortality.
08
#08
Blood Urea Nitrogen/Albumin Ratio and Mortality Risk in Patients with COVID-19.
HumanInfluence1.0
20
This study explored the relationship between blood urea nitrogen (BUN), albumin, and mortality risk in COVID-19 patients. Researchers found that elevated BUN levels were associated with increased in-hospital mortality, suggesting BUN could be a reliable predictor of clinical outcomes in COVID-19 cases.
09
#09
A Review of Routine Laboratory Biomarkers for the Detection of Severe COVID-19 Disease.
ReviewInfluence2.0
17
Researchers reviewed laboratory biomarkers for predicting severe COVID-19 disease. They highlighted that blood urea nitrogen (BUN) levels are important indicators of kidney function and disease severity in COVID-19 patients.
10
#10
Training Load Measures and Biomarker Responses during a 7-Day Training Camp in Young Cyclists-A Pilot Study.
Human
13
Clinical Trials (4)
4
Total Trials
668
Total Enrolled
A Clinical Study of Glycerol Phenylbutyrate in Chinese Patients With Urea Cycle Disorders
NCT06904027RECRUITING
Sponsor
Tongji Hospital
Enrollment
40
Started
2025
Primary outcome
Mean blood ammonia levels at month 3 after enrollment.
Urea Cycle Disorders
Hydroxyurea Therapy for Neurological and Cognitive Protection in Pediatric Sickle Cell Anemia in Uganda ( BRAINSAFE-II )
Sponsor
Global Health Uganda LTD
Enrollment
270
Started
2021
Primary outcome
The frequency, age specific prevalence and severity of Sickle Cell Vasculopathy manifested by New stroke as assessed by the Pediatric NIH Stroke Scale (PedNIHSS) over the 3-year study while on hydroxyurea treatment, compared to baseline assessments.
Sickle Cell Anemia in Children
BUN/Cr-based Hydration Therapy to Improve Outcome of Patients With Acute Ischemic Stroke
Sponsor
Chang Gung Memorial Hospital
Enrollment
288
Started
2021
Primary outcome
The rate of early neurological improvement at 72 hours after the onset of stroke
DehydrationIschemic Stroke
Novel Dose Escalation to Predict Treatment With Hydroxyurea
Sponsor
Baylor College of Medicine
Enrollment
70
Started
2013
Primary outcome
Time to patients reaching the maximum tolerated dose (MTD) of the medication
Sickle Cell Disease
Publication Trend
Research publications about Harnstoff over time
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