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Every result includes a professional assessment from a BIG-registered doctor. For treatment decisions, discuss your results with your GP.
Urea (BUN) Blood Test: What Does Your Level Mean?
BUN monitoring becomes increasingly important with age, as kidney function naturally declines over time. Medications commonly used by older adults, including certain blood pressure drugs and pain relievers, can also affect BUN levels, making regular testing valuable for healthy ageing.
What It Measures
This test measures the amount of urea in the blood. Urea is created when protein is broken down and is produced in the liver. Through the bloodstream it reaches the kidneys, where the blood is filtered and urea leaves the body through urine. Sometimes free urea is reported alongside urea. Because both the liver and the kidneys play a role, the urea value can say something about how well these organs work; it is most often used to look at kidney function.
Why It Matters
The amount of urea in the blood can give an impression of how well your kidneys filter waste products. Higher values may suggest the kidneys are not working well, but they can also relate to dehydration or to how much protein is in your diet. If you eat few proteins, the value can come out lower. Because urea is sensitive to several factors, it is usually viewed together with markers such as creatinine and eGFR. Your GP can help you place the result in context.
When to Test
BUN testing is commonly included in routine health screenings and comprehensive metabolic panels. It may also be recommended when symptoms of kidney dysfunction are present, such as changes in urination patterns, persistent fatigue, or unexplained swelling.
Additional testing may be appropriate for individuals with risk factors for kidney disease, including diabetes, high blood pressure, a family history of kidney problems, or long-term use of certain medications.
Symptoms
Low Levels
Loss of appetite or poor nutritional intake
Swelling related to fluid overload
High Levels
Nausea or vomiting
Confusion or difficulty concentrating
Decreased urine output
Swelling in the legs, ankles, or feet
Recommendations
Male
Low urea may indicate liver problems or overhydration. Consult your healthcare provider if symptomatic.
Elevated urea may indicate kidney dysfunction or dehydration. Consider hydration and kidney function evaluation.
Female
Low urea may indicate liver problems or overhydration. Consult your healthcare provider if symptomatic.
Elevated urea may indicate kidney dysfunction or dehydration. Consider hydration and kidney function evaluation.
Lifestyle Tips
Stay well hydrated throughout the day, as dehydration is a common cause of elevated BUN levels. Maintain a balanced diet with moderate protein intake, as very high protein consumption can increase BUN.
Manage blood pressure and blood sugar levels carefully, as both hypertension and diabetes are leading causes of kidney damage. Limit the use of over-the-counter pain medications such as NSAIDs, which may affect kidney function over time.