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Every result includes a professional assessment from a BIG-registered doctor. For treatment decisions, discuss your results with your GP.

Kidney

Urea (BUN) Blood Test: What Does Your Level Mean?

BUN is a kidney function marker that athletes should monitor regularly. Intense exercise, high-protein diets, and protein supplementation can all elevate BUN levels. Adequate hydration during training is essential for accurate results and optimal kidney function.

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

Fatigue and general weakness
Loss of appetite or poor nutritional intake
Swelling related to fluid overload

High Levels

Fatigue and persistent tiredness
Nausea or vomiting
Confusion or difficulty concentrating
Decreased urine output
Swelling in the legs, ankles, or feet

Recommendations

Male

If Low

Low urea may indicate liver problems or overhydration. Consult your healthcare provider if symptomatic.

If High

Elevated urea may indicate kidney dysfunction or dehydration. Consider hydration and kidney function evaluation.

Female

If Low

Low urea may indicate liver problems or overhydration. Consult your healthcare provider if symptomatic.

If High

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.

Frequently Asked Questions

Can eating a lot of protein raise my BUN levels?
Yes, a high-protein diet can increase BUN levels because more urea is produced as the body metabolises protein. This does not necessarily indicate kidney disease, but persistently elevated levels should be evaluated by a healthcare provider.
What is the difference between BUN and creatinine?
Both are waste products filtered by the kidneys, but they come from different sources. BUN comes from protein metabolism and is affected by diet and hydration, while creatinine comes from muscle metabolism and is generally more stable. Together, they provide a clearer picture of kidney function.
Can dehydration affect BUN results?
Yes, dehydration is one of the most common causes of elevated BUN. When you are dehydrated, the kidneys reabsorb more urea, leading to higher levels. Drinking adequate fluids before testing can help ensure accurate results.

Test Products

This marker is included in the following test panels.

Complete Health

360 Health

Broad health panel: hormones, thyroid, vitamins, lipids, liver, kidney, and blood count.

HbA1c (Glycated Hemoglobin) TSH (Thyroid Stimulating Hormone) Triglycerides Urea (BUN) Creatinine eGFR (Estimated Glomerular Filtration Rate) Free T4 (Thyroxine) LDL Cholesterol Liver Function Test (LFT) SHBG (Sex Hormone Binding Globulin) Vitamin B12 Vitamin D (25-OH) Free Testosterone Total Testosterone Free T3 (Triiodothyronine) Ferritin HDL Cholesterol Albumin Complete Blood Count (CBC)
€346,-