A blood urea nitrogen test is a blood test to measure the amount of urea nitrogen waste present in the blood. The blood urea nitrogen test, in short, “BUN,” is a simple, non-invasive test to check the functioning of kidneys and how effectively the proteins are metabolised. This kidney function test is now performed on serum samples, but the name remains as a blood urea nitrogen test. When the kidney fails to filter out the nitrogenous waste from the blood completely, it remains in the blood and circulates throughout the body giving rise to kidney-related disease and other circulation related problems.
What is the Blood Urea Nitrogen Test?
The blood urea nitrogen test, in short, “BUN,” is a simple, non-invasive test to check the functioning of kidneys and how effectively the proteins are metabolized. This kidney function test is now performed on serum samples, but the name remains as a blood urea nitrogen test.
How is urea nitrogen measured?
There are 2 Methods to measure urea nitrogen.
- 1. Photometry-based method: This method is based on the development of yellow chromogen when the diacetyl reacts with urea. The amount of yellow pigment produced is measured by auto analyzers through photometry. This method has a high accuracy rate but less specificity. The reason behind its low specificity is that the blood has hemoglobin which can have colorimetric interference. Due to this reason, this kidney function test is now performed on serum samples, but the name remains as a blood urea nitrogen test.
- 2. Enzyme-based method: The urea present in the blood is converted into carbonic acid and ammonia by the enzyme urease. The amount of ammonia and carbonic acids produced by the reaction is automatically quantified. This tells us the amount of urea and nitrogenous waste present in the blood.
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Specimen or sample Collection for a BUN Test
In order to collect the blood specimen for a blood urea nitrogen test, it is strictly advised not to take vials coated with sodium fluoride as it can interfere with the process because fluoride inhibits the urease enzyme.
Which two tests are carried out to check renal functions?
Two tests that can tell us about the renal function of the body are:
- 1. Serum creatinine test
- 2. BUN test
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The serum creatinine test and BUN test are the two tests that are considered the absolute indicators of kidney or renal functions. Most importantly, these tests are used to determine the renal status at any given interval. Hence, these two tests are frequently used in tracking renal disease progression.
What happens if blood urea nitrogen is high?
Elevated levels of blood urea nitrogen point out abnormalities in the functioning of kidneys and renal tubules. At times the abnormally elevated levels of urea nitrogen in blood could be due to reasons other than renal problems. These include,
- 1. Steroids use
- 2. Dehydration
- 3. Burn injuries
- 4. High-protein diet
- 5. Aging
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What is low urea nitrogen in blood tests?
Your doctor will recommend one more of the following medicines to increase the BUN levels if these levels are found to be low in your blood.
Medicines that can high up your blood BUN levels includes,
- 1. Amphotericin B
- 2. Antibiotics of class cephalosporins
- 3. Carbamazepine
- 4. Furosemide
- 5. Aldactone
- 6. Methyldopa
- 7. Methotrexate
- 8. Rifampin
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What does it mean when my urea nitrogen is high?
High urea nitrogen tests in the blood can be due to various other reasons apart from renal dysfunctions. These reasons include,
- 1. You might be on steroids
- 2. You might be dehydrated
- 3. Burn injuries are also the reason for elevated BUN levels
- 4. You might be on a high-protein diet
- 5. Aging is one of the reasons for increased BUN levels.
-
Frequently Asked Questions
Q.1. What is the Blood Urea Nitrogen Test?
The blood urea nitrogen test, also called as “BUN test,” is a simple, non-invasive test to check the functioning of kidneys and how effectively the proteins are metabolised. This kidney function test is now performed on serum samples, but the name remains as a blood urea nitrogen test.
Q.2. How is urea nitrogen measured?
There are 2 Methods to measure urea nitrogen.
- 1. Photometry-based method: This method is based on the development of yellow chromogen when the diacetyl reacts with urea. The amount of yellow pigment produced is measured by auto analyzers through photometry. This method has a high accuracy rate but less specificity.
- 2. Enzyme-based method: The urea present in the blood is converted into carbonic acid and ammonia by the enzyme urease. The amount of ammonia and carbonic acids produced by the reaction is automatically quantified. This tells us the amount of urea and nitrogenous waste present in the blood.
-
Q.3. How is the BUNtest sample collected?
Specimen or sample collection for a BUN test
In order to collect the blood specimen for a blood urea nitrogen test, it is strictly advised not to take vials coated with sodium fluoride as it can interfere with the process because fluoride inhibits the urease enzyme.
Q.4. Which two tests are carried out to check renal functions?
Two tests that can tell us about the renal function of the body are:
- 1. Serum creatinine test
- 2. BUN test
-
Q.5. What is the significance of the BUN test and serum creatinine test?
The serum creatinine test and BUN test are the two tests that are considered the absolute indicators of kidney or renal functions. Most importantly, these tests are used to determine the renal status at any given interval. Hence, these two tests are frequently used in tracking renal disease progression.
Q.6. What happens if blood urea nitrogen is high?
Elevated levels of blood urea nitrogen point out abnormalities in the functioning of kidneys and renal tubules. At times the abnormally elevated levels of urea nitrogen in blood could be due to reasons other than renal problems. These include,
- 1. Steroids use
- 2. Dehydration
- 3. Burn injuries
- 4. High-protein diet
- 5. Aging
-
Q.7. What is low urea nitrogen in blood tests?
Medicines that can high up your blood BUN levels includes,
- 1. Amphotericin B
- 2. Antibiotics of class cephalosporins
- 3. Carbamazepine
- 4. Furosemide
- 5. Aldactone
- 6. Methyldopa
- 7. Methotrexate
- 8. Rifampin
-
Q.8. What does it mean when my urea nitrogen is high?
High urea nitrogen tests in the blood can be due to various other reasons apart from renal dysfunctions. These reasons include,
- 1. You might be on steroids
- 2. You might be dehydrated
- 3. Burn injuries are also the reason for elevated BUN levels
- 4. You might be on a high-protein diet
- 5. Aging is one of the reasons for increased BUN levels.
-
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