Nephritis urea nitrogen 8.3mmol / L suggests elevated, may be physiological factors, kidney disease, blood volume deficiency or acute infectious diseases and other causes, need to treat the cause of the symptoms. 1. Physiological factors: a large amount of high protein food will lead to urea nitrogen over the normal level, this situation generally does not require treatment, standardize dietary habits and normal diet, the general value will return to normal. 2. Kidney disease: chronic renal failure, acute kidney injury, chronic glomerulonephritis, diabetic nephropathy, etc., can also lead to increased urea nitrogen. 3. Insufficient blood volume: cardiac failure, severe dehydration and other conditions will lead to insufficient blood volume, which will also reduce renal blood flow and easily cause urea nitrogen to rise. 4. Others: acute infectious diseases, upper gastrointestinal bleeding, high fever, severe trauma and other conditions, the body will also increase urea nitrogen. In addition, it is recommended that low-fat, low-salt diet, to reduce protein intake, it is best to choose high-quality protein, such as fish, lean meat, eggs, milk, usually have more rest, avoid overwork, to avoid the use of nephrotoxic drugs, which is conducive to slowing down the development of kidney disease. Nephritis urea nitrogen 8.3mmol / L suggest timely medical attention, under the guidance of the doctor to clarify the cause of the disease, symptomatic treatment.