High-urea nitrogen counts often indicate kidney dysfunction, explains Healthline. Symptoms of kidney dysfunction include frequent urination, discolored urine, restless legs, back pain and swelling in the extremities. However, a variety of conditions potentially cause high-urea nitrogen counts, and these in turn cause many other symptoms.
Other symptoms of kidney dysfunction include fatigue, muscle cramping, itchiness and lack of appetite, states Healthline. Conditions that inhibit kidney function, such as urinary tract obstruction, high blood pressure and diabetes, potentially cause high levels of urea nitrogen. However, heart failure, high-protein diets and dehydration also increase urea nitrogen counts, explains WebMD.
Low-urea nitrogen levels possibly indicate liver failure, a low-protein diet, malnutrition or excessive hydration, explains MedlinePlus. Pregnancy also sometimes causes low blood urea nitrogen levels, states WebMD.
Doctors usually test urea nitrogen counts by taking a blood or urine sample, explains MedlinePlus. Blood urea nitrogen tests check kidney function, while urine urea nitrogen tests check the protein balance in severely ill patients. Urine urea nitrogen tests require urine samples over a 24-hour period. The normal level of nitrogen in urine is between 12 and 20 grams per 24 hours, and normal blood urea nitrogen levels are from 6 to 20 milligrams per deciliter.