Blood urea nitrogen or a BUN test is ordered by a doctor, especially in cases when he or she deduces that an individual has kidney disease. So, what exactly does a BUN test measure, and what does it mean if there is a high BUN level? Everything you need to understand about a BUN test is explained below.
What Is A BUN Test?
A BUN test checks the level of nitrogen in the blood. Nitrogen comes from urea, a waste product that comes from the breakdown of protein. Furthermore, urea is manufactured in the liver before it is excreted via the urine.
BUN tests help doctors evaluate the health as well as the function of the kidneys. If the kidneys are not filtering toxins properly, then the BUN levels should be elevated. Conditions that cause elevated BUN values include a protein-rich diet, dehydration, and heart failure.
On the other hand, lowered BUN values indicate liver damage or disease. However, low values of a BUN test are normal during pregnancy, specifically during the second or third trimester.
Why Is It Done?
While a BUN test is sometimes part of a routine checkup, doctors are likely to recommend this test if they suspect that an individual has kidney disease. Other than that, this test is ordered for the following reasons.
- Evaluate the Normal Function of the Kidneys
- Evaluate the Progression of Kidney Disease
- Evaluate the Effectivity of the Kidney Disease Treatment
- Assess for Severe Dehydration
Results of a BUN Test
The average values of a BUN test are referred to as the reference range, which may vary from one lab to the next. Moreover, the results from a BUN test are checked against other tests as well as outside factors.
- Children: 5 to 18 mg/dL
- Adults: 10 to 20 mg/dL
Why Is It Bad?
What happens if the levels of urea are high in the blood? Well, it causes oxidative stress in the cells. Moreover, elevated BUN values indicate the presence of other medical conditions that warrant immediate treatment.
High values in a BUN might be indicative of an increased breakdown of protein, which is linked to a lowered immune function. It may likely lead to a heightened risk of infection in individuals with elevated BUN values.
Other than that, high values of BUN are linked to the increase of mortality, especially in patients who are critically ill. It is also associated with side effects in heart failure patients and individuals with atherosclerosis. Lastly, high BUN levels are linked to an increased risk of stroke in patients who have gone through heart surgery.
However, it is vital to take note that BUN values commonly increase as an individual grows older. BUN values are typically low in babies, approximately two-thirds of the level in healthy adults. On the other hand, adults over the age of 60 have a somewhat higher BUN value compared to young adults.
Symptoms of High BUN
An elevated BUN may already manifest itself in an individual through the following signs and symptoms.
- Swelling of the Extremities
- Poor Appetite
- Trouble Sleeping
- Restless Legs
- Frequent Urination
- Bone and Back Pain
- Joint Pain
- Muscle Cramps
- Discolored Urine (Foamy, Dark, or Bloody)
How to Decrease a High-Value BUN
Apart from medical treatments, there are methods to lower one’s BUN values. Consuming more water may help. Other than that, additional ways to decrease a high BUN value include the following.
1. Inhibit Arginase
Arginase helps convert L-arginine into urea. So, by cutting down on arginase, it directly results in a decrease of urea. Ginseng, cocoa, and citrus fruits are effective in inhibiting arginase. However, there is a drawback to this, since it leads to the accumulation of ammonia.
2. Reduce Protein Intake
Consuming excessive amounts of protein leads to elevated BUN values. So, to lower the level, try to cut back on eating meat. Go for vegetable patties rather than beef burgers. Also, consume more vegetables and fruits than poultry, red meat, dairy, and fish. Food that contains moderate amounts of protein include grains, nuts, and beans.
Before reducing your protein consumption, it is best to consult with your attending physician. Remember that the recommended daily intake of protein falls between 40 to 60 grams, and to lower an elevated BUN, you may have to reduce protein by half of the said range.
3. Avoid Stress and Maintain a Healthy Blood Pressure
In rare cases, high BUN values are due to high blood pressure and excess stress. It is best to have your blood pressure checked regularly. Also, if you constantly suffer from high blood pressure, then it is best to consult with your doctor. He or she will then recommend medications that will help stabilize your blood pressure. As for managing and avoiding stress, opt for relaxation exercises or counseling.
4. Stay Well Hydrated
As mentioned, dehydration can result in an elevated BUN. Thus, it is vital to stay well hydrated to maintain electrolyte and water balance in the cells. If you are experiencing persistent diarrhea or are taking diuretics, then you must drink enough water to avoid dehydration.
Aside from the BUN test, a creatinine test is also ordered to evaluate the function and health of the kidneys further. Another test includes an electrolyte test that checks calcium, potassium, and sodium levels. There is also the renal panel which better helps the attending physician understand how well the kidneys are working. Imaging tests which include a CT scan, an MRI, or an x-ray are also recommended, especially in cases where an individual has a current medical condition involving the kidneys.