Blood Urea Nitrogen (BUN) Test: About This Test (2024)

FAQs

Blood Urea Nitrogen (BUN) Test: About This Test? ›

The blood urea nitrogen (BUN) test measures how much urea nitrogen is in your blood. It helps a healthcare provider determine if your kidneys are working as they should. BUN levels vary according to your age and sex. Abnormal levels may indicate a health condition, including kidney damage.

The BUN test measures the amount of urea nitrogen in your blood. Urea nitrogen is a waste product that your kidneys remove from your blood. Higher than normal BUN levels may be a sign that your kidneys aren't working well. People with early kidney disease may not have any symptoms.

However, if a patient's BUN levels exceed their normal baseline and their creatinine levels are elevated, it indicates potential kidney failure. A BUN level higher than 20 mg/dL suggests that the kidneys may not be functioning at optimal capacity.

Low values

A low BUN value may be caused by a diet very low in protein, by malnutrition, or by severe liver damage. Drinking too much liquid may cause overhydration and cause a low BUN value. Women and children may have lower BUN levels than men because of how their bodies break down protein.

The BUN, then, is roughly one-half (28/60 or 0.446) of the blood urea. The normal range of urea nitrogen in blood or serum is 5 to 20 mg/dl, or 1.8 to 7.1 mmol urea per liter.

Proper hydration is the most effective way to lower BUN levels. A low-protein diet can also help lower BUN levels. A medication wouldn't be recommended to lower BUN levels. However, abnormal BUN levels don't necessarily mean you have a kidney condition.

A high BUN level is generally caused by impaired kidney function; however, it can also be due to a high-protein diet; dehydration; congestive heart failure; or increased protein breakdown caused by gastrointestinal bleeding, trauma, or corticoid therapy.

General reference ranges for a normal BUN level are as follows: Adults up to 60 years of age: 6-20 mg/dL. Adults over 60 years of age: 8-23 mg/dL.

A low-protein diet can also help reduce high BUN levels. Healthy low-protein foods include: Grains: Oats, rice and pasta. Fruits: Apples, berries and bananas.

Typically, the ratio of BUN to creatinine should be between 10:1 and 20:1. If it's lower or higher than that, it may mean you have a problem with your kidneys or you may not be drinking enough water.

Is a low BUN OK? ›

Having a low BUN level is usually not serious. However, if you want to raise your levels, you should eat more protein and improve the health of your liver by drinking less alcohol and losing weight.

Low urea levels are not common and are not usually a cause for concern. They can be seen in severe liver disease or malnutrition but are not used to diagnose or monitor these conditions. Low urea levels are also seen in normal pregnancy. Urea levels increase with age and also with the amount of protein in your diet.

BUN levels may be high due to heart failure, dehydration, or a high protein diet. Low BUN levels could be due to liver disease.

A level surpassing the BUN normal range of 6-20 mg/dL indicates kidney problems. If your BUN test shows extreme results, it might signal kidney failure. For example, a BUN level of 75 mg/dL is highly considered alarming. It may suggest immense kidney damage to the extent of possibly relying on dialysis.

Results of the BUN test are measured in milligrams per deciliter (mg/dL) in the United States and in millimoles per liter (mmol/L) internationally. In general, around 6 to 24 mg/dL (2.1 to 8.5 mmol/L ) is considered normal. But normal ranges may vary, depending on the reference range used by the lab and your age.

The normal range of blood urea nitrogen (BUN) is between 7 and 20 mg/dL or 2.5 and 7.1 mmol/L. There may be slight variations between labs. A decline in kidney function can cause an increase in BUN levels. There is no definite value of BUN that would diagnose kidney failure.

Values consistently around 20:1 may be early warning signs of kidney disease. Any value above 20:1 indicates that you are dehydrated, and may also be developing kidney-related or other health issues. A BUN/creatinine ratio of 50:1 or above is dangerously high that requires immediate medical attention.

Results of the BUN test are measured in milligrams per deciliter (mg/dL) in the United States and in millimoles per liter (mmol/L) internationally. In general, around 6 to 24 mg/dL (2.1 to 8.5 mmol/L ) is considered normal. But normal ranges may vary, depending on the reference range used by the lab and your age.

Patients with uremia may present with various symptoms, including nausea, vomiting, fatigue, anorexia, weight loss, dysgeusia (bad taste in the mouth), chest pain, palpitations, dyspnea, muscle cramps, restless legs, pruritus, easy bleeding, or mental status changes.