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Blood Urea

(Urea)

You need to provide

Blood

This test is for

Male, Female

Understanding Blood Urea

What is Blood Urea?

A Blood Urea test measures the level of urea in the blood. This test is done to detect any kidney disease or damage, or if you are undergoing treatment for an already existing kidney disease. This test is performed as part of a routine health checkup to determine your kidney function.

Blood urea is a waste product in your body. It is the final breakdown product of the amino acids that are present in proteins. When proteins break down, they produce nitrogen in the form of ammonia in the liver. This nitrogen combines with other chemicals in the liver to form the waste product called urea. The urea is released into the blood and carried to the kidneys where it is filtered out of the blood and flushed out through urine. Usually, healthy kidneys remove more than 90% of the urea the body produces; therefore, determining blood urea levels can show how well your kidneys are working.

Your doctor may advise a Blood Urea test if you experience symptoms such as frequent urination, swelling in the ankles and feet, restless legs during sleep, mental confusion, and pain in the middle back. The doctor may also recommend this test if you are at risk of kidney disease; are suffering from diabetes, have high blood pressure or heart disease; or have a family history of kidney disease. The test may also be used to determine the effectiveness of dialysis treatment. Usually, no special preparation is required for a Blood Urea test; eat and drink as per your daily routine.

Test result ranges are approximate and may differ slightly between different labs depending on the methodology and laboratory guidelines. Talk to your doctor about your specific test results. Narrate your complete medical history to help the doctor correlate your clinical and laboratory findings. The test results will help them determine your medical condition, make recommendations for lifestyle modifications such as diet and exercise, decide whether or not medication will be required to manage your kidney health, and formulate your overall treatment plan.

What is Blood Urea used for?

A Blood Urea test is done:

As part of routine health checkups.
In the case of signs and symptoms of kidney disease.
To screen for kidney disease if you have risk factors like obesity, diabetes, high blood pressure, or a family history of kidney disease.
To check the effectiveness of undergoing treatment for kidney diseases.
To help determine the effectiveness of dialysis if someone is receiving hemodialysis or peritoneal dialysis.

What does Blood Urea measure?

A Blood Urea test measures the level of urea in the blood. Urea is a byproduct of protein metabolism. Proteins you consume in your diet are digested and converted into amino acids, which are then utilized by the body. This metabolic process produces a toxic byproduct known as ammonia. Ammonia is then rapidly converted into urea by your liver. Urea is comparatively less toxic than ammonia and is transported to the kidneys via the blood. The kidneys then filter it out through the urine. This process continues and the body keeps producing and eliminating urea, maintaining its low and steady levels in the blood.

Interpreting Blood Urea results

Interpretations

Normal range (Approx.):

AGE	REFERENCE RANGE (mg/dL)
0-1 week	3-25
1 week to 1 year	4-19
1-12 years	5-18
12-60 years	6-20
60-90 years	8-23
>90 years	10-31

Reference range may vary from lab to lab*

Higher than normal BUN levels indicate impaired kidney function which means the kidneys are unable to effectively filter waste products out of the blood.

Lower than normal BUN levels are usually clinically insignificant. However, lower levels may be associated with large scale liver conditions in some cases.

Answers to Patient Concerns & Frequently Asked Questions (FAQs) about Blood Urea

Frequently Asked Questions about Blood Urea

Q. What is a blood urea test used for?

A blood urea test is a routine checkup to see if your kidneys are working properly or to detect kidney-related diseases.

Q. When should I get a blood urea test done?

You may need a blood urea test if you are suspected of kidney disease or have symptoms such as swelling or puffiness around eyes, ankles, and wrist; frequent urination; back pain; loss of appetite; or high blood pressure.

Q. Is there any risk associated with a blood urea test?

There is no risk associated with a blood urea test. However, you may feel slight pain at the site where a needle is pricked, which is usually self-limiting. Rarely, some people may experience swelling or bruising at the injection site. Applying ice over the area 3-4 times for about a week may provide relief. If it does not get better, consult your doctor.

Q. What happens if my blood urea level is high?

Always consult your doctor if you have higher-than-normal blood urea. High blood urea levels may indicate underlying health issues, such as acute or chronic kidney failure, urinary tract obstruction, chronic glomerulonephritis, or dehydration.

Q. What happens if my blood urea level is low?

If your blood urea level is lower-than-normal, it might indicate a poor diet (inadequate protein or high carbohydrate intake), issues with absorbing nutrients from your diet, or severe liver disease. Blood urea levels may be low in pregnant women too.

Q. What can produce false results in the BUN Test?

False results can appear in the BUN Test due to a number of factors, including taking a protein rich diet, use of steroids, dehydration, burn injury, aging, use of certain medications like carbamazepine, methotrexate, rifampin, etc., and during pregnancy.

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References

Blood Urea Nitrogen - Health Encyclopedia - University of Rochester Medical Center. Rochester.edu. Published 2019. [Accessed 20 Feb. 2023]. Available from: https://www.urmc.rochester.edu/encyclopedia/content.aspx?contenttypeid=167&contentid=urea_nitrogen_serum

Blood urea nitrogen (BUN) test | American Kidney Fund. www.kidneyfund.org. Published 05 Jan. 2022. [Accessed 20 Feb. 2023]. Available from: https://www.kidneyfund.org/all-about-kidneys/tests/blood-urea-nitrogen-bun-test