What is Urea Blood Test
Blood Urea Nitrogen test is used to measure the levels of nitrogen in the blood which comes from urea. This test is also named as BUN test. Urea is produced as a result of protein breakdown in the body. Urea passes out in the urine from the body. This article gives information about the urea blood test.
This test is used to check how well the kidneys are functioning. BUN level rises if the urea is not removed from the blood by the kidneys. Dehydration, high protein diet or heart failure can also increase the levels of BUN. Liver damage or disease may lower the BUN level. These low levels can be seen mostly during pregnancy.
Normal levels of blood urea is between 3.5 to 6.5 mmol/litre i.e 20 to 30 mg/dL.
Ratio of blood urea nitrogen and creatinine (BUN: creatinine)
A BUN test is done with a creatinine test. Creatinine levels in the blood also show how well the kidneys are working. Creatinine and BUN tests are to be done together to know their ratio. This ratio helps the doctor to check problems that include dehydration, which may result in abnormal levels of creatinine and BUN.
Why urea blood test is performed?
This test is used to:
- Check whether the kidneys are functioning normally.
- Check if the kidney disease or damage is getting worse.
- Check if the treatment or medicine for the kidney dysfunction is working.
- Check whether severe hydration is present. Due to dehydration BUN levels increase compared to creatinine levels. It results in a high ratio. Kidney dysfunction or urine flow blockage from the kidney increase both the levels of creatinine and BUN.
Preparation for the test
Don’t eat meat or protein for 24 hours before undergoing urea blood test.
It is good to go for blood testing. If you don’t go for the test, you may not know the normal blood test range.