summary
A common blood test, the blood urea nitrogen (BUN) test reveals important information about how well your kidneys are working. a bread test measures the amount of urea nitrogen in the blood.
this is how your body normally forms and disposes of urea nitrogen:
- Your liver makes ammonia, which contains nitrogen, after breaking down proteins used by your body’s cells.
- nitrogen combines with other elements, such as carbon, hydrogen, and oxygen, to form urea, which is a chemical waste product.
- urea travels from the liver to the kidneys through the bloodstream.
- Healthy kidneys filter urea and remove other waste products from the blood.
- filtered waste products leave your body through urine.
- if your doctor suspects that you have kidney disease or damage
- if your kidney function needs to be tested, especially if you have a chronic condition such as diabetes or high blood pressure
- to help determine the effectiveness of dialysis treatment if you are receiving hemodialysis or peritoneal dialysis
- as part of a group of blood tests to help diagnose other conditions, such as liver damage, urinary tract obstruction, congestive heart failure, or gastrointestinal bleeding, although an abnormal muffin test result alone does not confirm none of these conditions
- dehydration, as a result of not drinking enough fluids or for other reasons
- urinary tract obstruction
- congestive heart failure or recent heart attack
- gastrointestinal bleeding
- shock
- severe burns
- certain medications, such as some antibiotics
- a diet rich in protein
A bread test can reveal if your urea nitrogen levels are higher than normal, suggesting that your kidneys may not be working properly.
why is it done
you may need a bow test:
If kidney problems are the primary concern, blood creatinine levels will likely also be measured when blood urea nitrogen levels are tested. Creatinine is another waste product that healthy kidneys filter out of the body through urine. high levels of creatinine in the blood can be a sign of kidney damage.
Your doctor may also test how well your kidneys are removing waste from your blood. To do this, you may have a blood sample taken to calculate your estimated glomerular filtration rate (GFR). gfr estimates the percentage of kidney function you have.
how do you prepare
If your blood sample is being tested for bun only, you may eat and drink normally before the test. If your blood sample will be used for further testing, you may need to fast for a certain period of time before the test. your doctor will give you specific instructions.
what you can expect
During the bow tie test, a member of your health care team takes a blood sample by inserting a needle into a vein in your arm. the blood sample is sent to a laboratory for analysis. you can return to your usual activities immediately.
results
Muffin test results are measured in milligrams per deciliter (mg/dl) in the united states and millimoles per liter (mmol/l) internationally. in general, about 6 to 24 mg/dl (2.1 to 8.5 mmol/l) is considered normal.
but normal ranges can vary, depending on the reference range used by the lab and your age. ask your doctor to explain the results.
Burea nitrogen levels tend to increase with age. babies have lower levels than other people, and the range in children varies.
Usually, a high level of pan means that your kidneys are not working well. but the raised bun can also be due to:
If you are concerned about kidney damage, ask your doctor what factors may be contributing to the damage and what steps you can take to try to control them.
