Understanding the Blood Urea Normal Range: Causes of High/Low & What They Mean

The blood urea nitrogen test is one of the kidney function tests performed to evaluate the amount of urea nitrogen in your blood sample. It allows healthcare professionals to determine is your kidneys are functioning well. The exact blood urea nitrogen (BUN) levels in the blood differ depending on your gender and age. Abnormal BUN levels may be a sign of certain health conditions, such as kidney damage.

Testing urea levels, particularly through the blood urea nitrogen test, is essential for examining kidney function and determining potential health issues. This test, which measures, helps diagnose kidney-related conditions, track the effectiveness of ongoing treatment, and evaluate overall protein metabolism and hydration.

This article covers the information about the blood urea nitrogen test, why understanding the blood urea normal range is vital, high and low levels, causes, and symptoms, so don’t miss out.

Blood urea is a waste product of your body that is formed as your body breaks down the proteins that you consume through food. It develops in the liver and is transported to the kidneys through the blood, where it gets filtered out and eliminated from the body through urine.

Blood urea levels are significant markers that help healthcare professionals understand kidney function. The presence of urea nitrogen in the blood is usually normal; however, too high urea nitrogen levels in the blood indicate that your kidneys are not functioning well and may negatively impact your kidney health.

The major difference between urea and blood urea nitrogen is what they assess. BUN evaluates the nitrogen part of urea (a fraction of complete urea), and urea measurement means the complete urea molecule. Generally, the urea levels are almost twice the BUN levels, as urea comprises double the nitrogen atoms.

Usually, the blood urea nitrogen test is recommended during regular health checkups as a part of a basic metabolic panel blood test or a comprehensive metabolic panel test. Your healthcare provider may recommend the BUN test if they are suspicious that you have a greater risk of developing kidney disease.

The initial stages of kidney problems may not show symptoms, but certain factors can put you at a greater risk, such as diabetes, heart disease, high blood pressure, and a family history of kidney conditions.

If you are experiencing the symptoms of kidney disease, it is advised to get a BUN test. These symptoms include foamy pee, blood in the urine, a frequent urge to pee more, loss of appetite, fatigue, swelling in the hands, feet, and ankles.

Typically, the normal BUN test range in adults ranges between 6-24 mg/dL. It may slightly vary depending on the sex and age of the individual. Typically, the normal range in adult males ranges between 8-24 mg/dL, and in adult females it ranges between 6-21 mg/dL. The typical normal range of blood urea in children (1-17 years) ranges between 7-20 mg/dL. The specific reference range and the general guidelines may slightly vary from laboratory to laboratory. So, it's better to consult a doctor or healthcare provider for the interpretation of BUN test results.

Generally, in adults, it ranges between 7-20 mg/dL, in children, it ranges between 5-18 mg/dL, and in elderly individuals, higher levels may be found due to age-associated reduced kidney function.

The normal range in adults ranges between 7-20 mg/dL, and it may slightly vary depending on age, gender, hydration level, and kidney function.

Normal BUN range in adults ranges between 6-20 mg/dL, and the normal ranges may slightly vary depending on age, gender, and the laboratory’s reference range. Children usually have slightly lower BUN levels, and older adults may have slightly higher BUN levels.

Typically, it's similar to males; however, physiological factors such as pregnancy may affect the blood urea normal value in females. The blood urea normal range in adult females ranged between 6-21 mg/dL.

High BUN levels indicate problematic or diminished kidney function, and they may be associated with various underlying health conditions. Although high blood urea is associated with kidney issues, it may also be elevated because of certain medications, high-protein diets, and dehydration.

• Kidney dysfunction or kidney failure
• Dehydration (excessive fluid loss or low fluid intake)
• High intake of protein
• Heart failure (improper kidney function and elevated BUN
• Gastrointestinal bleeding

Associated symptoms include high fatigue, nausea and vomiting, loss of appetite, muscle weakness, muscle cramps, and swelling in hands, feet, and ankles. Some individuals may experience confusion, shortness of breath, difficulty concentrating, and skin issues.

Generally, low BUN levels range between 7 mg/dL and indicate malnutrition, overhydration, or liver disease. It usually suggests protein metabolism-related issues and conditions that involve blood dilution. Low BUN  levels may require further investigation to detect the underlying cause and accurate treatment.

• Liver dysfunction
• Malnutrition
• Overhydration
• Pregnancy

Common symptoms of low urea levels include weakness, fatigue, dizziness, confusion, muscle cramps, nausea, and vomiting.

Hypouricemia or low urea levels are usually not a major cause for concern; however, they can be a sign of an underlying health condition and may necessitate further investigation. Low BUN levels are associated with malnutrition, overhydration, liver dysfunction, and pregnancy.

Urea is nitrogen waste formed in the liver due to protein metabolism and is filtered by the kidneys and eliminated through urine. It is an important component of urine and is discarded by the kidneys. The urea cycle involves a series of biochemical reactions that are vital for ammonia conversion.

Urea is formed through the urea cycle in the liver, and the cycle involves enzymatic reactions converting ammonia into urea. This entire process is essential for nitrogen balance in the body and to prevent ammonia toxicity.

Urea is the prime nitrogenous waste in humans, and it is filtered from the blood through the kidneys and excreted via urine. Urea has an important role in osmoregulation and maintaining water balance.

The urea is filtered from the blood by the kidneys and is daily eliminated, around 25 to 30 grams of urea through urine. The concentration of urea in urine is affected by protein consumption and hydration.

Creatinine and urea are waste products formed as a result of metabolism, and these are closely associated with kidney function and glomerular filtration rate.  Healthy kidneys filter urea and creatinine from the blood very well, sustaining normal levels in the body. Improper kidney function raises the levels of creatinine and urea in the blood, leading to potential kidney issues. The ratio of urea to creatinine is a significant indicator of how well your kidneys are working.

Urea of the BUN test is performed to evaluate kidney function and the overall health of a person. The test is performed by a medical professional and involves drawing a sufficient amount of blood sample by inserting a needle in your vein, commonly from the arm. Then the blood sample is sent to the laboratory for analysis. The results are usually available in 1-2 days, depending on the city and laboratory.

The BUN test assesses the urea nitrogen in your blood, which indicates kidney and liver health. If you have persistent high or low BUN levels or you are experiencing one or more symptoms of kidney or liver disease, it's time to consult a doctor. A healthcare provider can guide you about the need for further investigations, such as a liver function test, estimated glomerular filtration rate, or creatinine. If your BUN test results are more or less than the normal range, talk to your doctor to get the right advice and accurate treatment. They can help you with the proper evaluation of your BUN test results and management of your underlying condition.

Urea is a useless product that is created due to the breakdown of protein. Having too high blood urea nitrogen levels in the blood indicates certain health concerns. Interpreting BUN test results helps identify kidney and liver health issues. High BUN levels signify kidney dysfunction, dehydration, and high protein intake, while low BUN levels indicate overhydration, liver problems, and malnutrition. If you have kidney or liver disease-associated symptoms or you are at risk of developing kidney disease or liver problems, it is advised to get the BUN test for accurate diagnosis and the right treatment plan. Consult your healthcare provider for result interpretation and proper treatment and management of the underlying conditions.