Exam Quick Guide

A blood urea nitrogen (BUN) exam measures the corporeality of urea in a sample of blood. Urea is a waste that forms as role of the body's natural process of breaking downwards proteins. It is as well referred to equally urea nitrogen and is filtered out of the blood past the kidneys.

A BUN test is most oft interpreted together with creatinine to help assess how well the kidneys are working. While BUN tin be tested independently, it is normally included in a console with other measurements, which offers a more extensive evaluation of the condition of your body.

About the Examination

Purpose of the test

A blood urea nitrogen test tin provide insight into how well the kidneys are working. The test may be used for diagnosis, screening, and/or monitoring. For these uses, BUN alone is mostly less informative than BUN taken with other measurements related to kidney function.

Diagnosis is the term that describes the process of finding the crusade when symptoms have already developed. BUN may be measured if y'all have symptoms of kidney affliction such as urinary changes, swelling in your artillery or legs, musculus cramps, or frequent episodes of fatigue.

Screening is trying to notice a wellness business before signs or symptoms have appeared. A BUN test equally part of a basic metabolic panel (BMP) or comprehensive metabolic panel (CMP) may exist prescribed during regular medical check-ups to screen for potential kidney conditions. Screening may be prescribed for people who take a college risk of kidney disease because of diabetes, cardiovascular problems, or a family unit history of kidney disease.

Monitoring is a style for a physician to track how a patient's condition changes. Measuring blood urea nitrogen may be function of observing kidney function over time. A BUN test can provide relevant information for evaluating response to handling for kidney problems.

Tests of kidney function, including a measurement of blood urea nitrogen, may also be used to monitor for side furnishings when you begin a new medication that can affect the kidneys.

What does the examination mensurate?

Equally the examination name indicates, a BUN test measures urea nitrogen in the blood. Urea, oftentimes called urea nitrogen, is a waste material production that is produced as a result of the breakdown of proteins in the body.

The kidneys piece of work to filter urea out of the blood then that information technology can exist cleared out of the body in the urine. Equally this process unfolds, it'southward normal for some urea to be in the claret. But when BUN levels are too high, information technology can be an indication that the kidneys are not functioning properly.

Although BUN can be tested individually, information technology is more mutual for it to be measured forth with other substances in the blood that tin can reflect the functioning of the kidneys.

When should I get a claret urea nitrogen exam?

Claret urea nitrogen is most commonly measured as part of the basic or comprehensive metabolic console. These tests involve 8 and xiv measurements respectively and provide insight into multiple bodily systems, including kidney function.

A panel of tests with a BUN measurement included may be appropriate if you have symptoms of kidney disease. In improver, a exam panel with BUN may exist used to help with diagnosis when you have full general symptoms or are beingness evaluated in an emergency room or urgent care.

Your doctor may recommend screening tests including a BUN measurement if y'all have adventure factors for kidney disease such as a family history of kidney problems, diabetes, or cardiovascular issues like high blood force per unit area.

Your doctor may also prescribe screening tests with a BUN measurement during routine medical exams. Though this blazon of testing is ordinarily washed, at that place is no articulate research showing that the benefits of routine screening are greater than its downsides, including the costs of testing and potential for unnecessary follow-upwardly procedures.

If you take previously had an abnormal BUN test or accept a known kidney problem, repeat testing at regular intervals may be appropriate in gild to monitor your situation and current kidney function.

Finding a Blood Urea Nitrogen Test

How to go tested

Testing for claret urea nitrogen is ordinarily prescribed by a doctor, and the examination is performed using a sample of claret that is fatigued from a vein in your arm. The blood draw normally takes place in a medical setting similar a medico'due south office or laboratory.

While BUN tin can be tested alone, in most cases it is part of a console of tests that includes multiple measurements from the same claret sample. For example, BUN is a standard component of the basic metabolic console and comprehensive metabolic panel.

Can I accept the test at abode?

At-home tests are available that include a measurement of claret urea nitrogen. These tests do non typically mensurate BUN alone but rather involve a few additional measurements that are related to kidney function. For an at-dwelling BUN test, you fix a blood sample from the finger and transport it by post to a lab.

At-home tests that measure BUN are available without a prescription, but information technology is nonetheless recommended that y'all talk with your doctor before and after taking an at-home test. If you lot have an abnormal outcome, your doctor may want to repeat the test or conduct more comprehensive testing using a blood sample taken from a vein.

How much does the exam cost?

Blood urea nitrogen testing does non take a prepare cost. Instead, the cost depends on where you have the test taken and whether y'all accept health insurance coverage. The cost will also vary based on whether BUN is tested lonely or in a panel with other measurements.

The full cost of a BUN test includes several different components including charges for an role visit, a blood draw by a technician, and laboratory analysis. These costs are often covered by health insurance if the test has been prescribed for yous by your dr..

Check with your insurance company and your doctor'southward part for more detailed information about test costs, and make sure to ask whether you volition be responsible for a deductible or copay.

At-dwelling tests that include BUN in a panel of measurements related to kidney wellness are available for effectually $100, which usually includes the costs for shipping your sample.

Order your calm health test online

A convenient, affordable, and discreet style of getting accurate exam results quickly.

  • Lodge the correct examination for you.

    We have a broad range of tests to embrace your health needs. Order with next 24-hour interval delivery and avoid sitting in a doctor'due south office or clinic.

  • Collect your sample

    Activate your test and collect your sample in the morning. Return your sample on the same mean solar day, using the prepaid shipping label provided.

  • Discreet Packaging

    Complimentary next day shipping and confidential results in 2-5 days

  • discount icon

    Get xxx% Off

    When yous use the promo lawmaking TESTING30

  • Discreet Packaging

    Complimentary next twenty-four hours shipping and confidential results in 2-5 days
  • Trustworthy Medical Support

    Existent-time support services from our national network of physicians and nurses
  • Health Records You Control

    Privacy at your fingertips, integrated with your option of apps and wearables

Taking a Blood Urea Nitrogen Test

This exam measures urea nitrogen in the blood, so testing requires a blood sample. This sample is taken from a vein in your arm with a needle.

If BUN is beingness measured equally office of an at-dwelling house examination, the sample is a drop of blood taken from your finger.

Before the exam

When scheduling your exam, you should tell your doctor nigh any prescription drugs, over-the-counter medications, and/or dietary supplements that y'all usually accept. Some of these can touch a BUN test, and so your doctor may ask you to modify your medication schedule before the test.

Other types of preparations, including fasting, are not normally needed for a test of BUN alone. Nonetheless, if BUN is being tested with other measurements such equally in a bones or comprehensive metabolic panel, you lot volition likely be instructed to fast for 8-12 hours before the blood depict.

For an at-home test, you should inquire your doctor or bank check with the included instructions for details about any required preparations, including whatsoever changes to your medications.

During the examination

Afterwards beingness seated, a technician will necktie an elastic band around the top part of your arm in order to increment blood flow in your veins. They will use an clarified to disinfect the area of your arm where the blood will exist drawn, which is typically on the inside function of your elbow.

The technician will insert a sterile needle into your vein and utilize it to remove a pocket-sized vial of blood. After that, the needle will be removed, and the collection is finished.

Overall, the examination usually takes simply a few minutes during which y'all may feel some temporary pain or a stinging sensation.

For an at-home exam, yous'll utilise an included device with a very small needle to prick your fingertip. Y'all then put a drop of blood on a examination strip that is then mailed to a laboratory.

After the exam

Applying pressure to the puncture site with a cast or cotton swab tin preclude bleeding later on your claret has been drawn. Y'all may discover some bruising or tenderness in your arm, only if this occurs, information technology tends to go away quickly.

You tin ordinarily return to your normal activities, including working and driving, after the test. Consider bringing a snack for after the test if you were instructed to fast beforehand.

Information technology is uncommon to have whatever ongoing side effects later an at-dwelling house BUN examination, but if your fingertip continues to bleed, you lot tin apply pressure with a small bandage.

Blood Urea Nitrogen (BUN) Test Results

Receiving test results

After your blood draw, you will typically become the results within a few business days. Information technology is common to get a re-create of the test report by mail or have admission to information technology online through a health intendance portal. Your physician's part may too call or ship you a secure electronic bulletin to provide information well-nigh your results.

Because an at-dwelling house test kit has to be sent by mail to the lab, it is normal for it to take a couple of additional days to receive your test results. In most cases, the results are available online or through a smartphone app.

Interpreting exam results

The test report should include a line for blood urea nitrogen that shows the level establish in your sample equally well every bit the laboratory's reference range. BUN is measured in milligrams per deciliter of blood (mg/dL).

Working with your physician is the best style to empathise the significance of your BUN test. The American Board of Internal Medicine lists a typical reference range for blood urea nitrogen as viii to 20 mg/dL. However, this range is not universal. Labs tin can apply different methods to measure out BUN, and what constitutes a normal result can vary from lab to lab.

If you had a console test, you should meet separate test results for whatever other measurements taken forth with blood urea nitrogen. Each test component will accept the listed reference range for the laboratory that conducted your test.

Your doctor can discuss your BUN levels and how they relate to your overall health, whatsoever symptoms you have, and other exam measurements. This is important because BUN levels alone are not a consistent predictor of kidney office. Elevated BUN tin occur with kidney bug, but it can also happen from eating lots of protein, taking certain medications, or from other issues like dehydration or burns. BUN levels frequently rise with aging too.

Independently, blood urea nitrogen may non reflect kidney function. For this reason, information technology is often interpreted in the context of other measurements, such as creatinine, a breakup product of the muscle, that is filtered by the kidneys. In some cases, the doctor may look at the ratio of BUN to creatinine to help determine the underlying cause of the altered kidney function.

Abnormally low levels of BUN can be a sign of malnutrition, lack of poly peptide in the nutrition, and liver disease. Therefore, other tests included in a panel test similar the comprehensive metabolic panel may provide helpful information for understanding the significance of depression claret urea nitrogen.

Are test results accurate?

Laboratory methods for measuring BUN are considered to be reliable for medical estimation and apply. While no medical test is perfect, protocols exist to reduce errors in cartoon your claret, preparing your sample, and analyzing it in the lab.

Do I need follow-up tests?

If you have an abnormal issue on your BUN test, you lot may need follow-upward testing. This could include an expanded panel of measurements along with BUN if this kind of testing was non conducted initially. Tests to farther evaluate kidney office, such equally the estimated glomerular filtration charge per unit (eGFR), may be performed.

Depending on the interpretation of the examination results, other laboratory tests or imaging tests may be needed to definitively diagnose any underlying condition that is affecting your wellness.

Questions for your doctor near test results

Some questions that may be helpful when you lot go over your blood urea nitrogen test results with your doc include:

  • Was my BUN level normal or abnormal?
  • Were any other measurements taken along with BUN?
  • What exercise the exam results mean for my kidney part?
  • If my test was aberrant, what is the about likely caption for that outcome?
  • Should I repeat the BUN test at whatever point or have any other follow-up tests?

Related Content

View Sources

A.D.A.M. Medical Encyclopedia. Comprehensive metabolic panel. Updated January 26, 2019. Accessed May 13, 2021. https://medlineplus.gov/ency/article/003468.htm

A.D.A.Thou. Medical Encyclopedia. Basic metabolic panel. Updated April 29, 2019. Accessed May 13, 2021. https://medlineplus.gov/ency/commodity/003462.htm

A.D.A.K. Medical Encyclopedia. BUN – claret test. Updated April 29, 2019. Accessed May 13, 2021. https://medlineplus.gov/ency/article/003474.htm

American Board of Internal Medicine. ABIM laboratory test reference ranges. Updated January 2021. Accessed May thirteen, 2021. https://www.abim.org/Media/bfijryql/laboratory-reference-ranges.pdf

Gounden V, Bhatt H, Jialal I. Renal part tests. In: StatPearls. Updated July xx, 2020. Accessed May 19, 2021. https://www.ncbi.nlm.nih.gov/books/NBK507821/

Hosten AO. Chapter 193: BUN and Creatinine. In: Walker HK, Hall WD, Hurst JW, eds. Clinical Methods: The History, Physical, and Laboratory Examinations. 3rd edition. 1990. Accessed May xix, 2021. https://www.ncbi.nlm.nih.gov/books/NBK305/

Inker LA, Perrone RD. Lab interpretation: high blood urea nitrogen in adults. In: Sterns RH, ed. UpToDate. Updated June 26, 2019. Accessed May 18, 2021. https://www.uptodate.com/contents/high-blood-urea-nitrogen-in-adults

Inker LA, Perrone RD. Cess of kidney function. In: Sterns RH, ed. UpToDate. Updated Apr 29, 2021. Accessed May 19, 2021. https://world wide web.uptodate.com/contents/assessment-of-kidney-function

MedlinePlus: National Library of Medicine. BUN (claret urea nitrogen). Updated July 30, 2020. Accessed May thirteen, 2021. https://medlineplus.gov/lab-tests/bun-blood-urea-nitrogen/

MedlinePlus: National Library of Medicine. Comprehensive metabolic panel (CMP). Updated March 2, 2021. Accessed May 13, 2021. https://medlineplus.gov/lab-tests/comprehensive-metabolic-panel-cmp/

Ask a Laboratory Scientist

Ask a Laboratory Scientist

This form enables patients to ask specific questions about lab tests. Your questions volition be answered by a laboratory scientist as part of a voluntary service provided past one of our partners, American Society for Clinical Laboratory Science. Please allow 2-iii business days for an email response from one of the volunteers on the Consumer Information Response Team.

Send Us Your Question