High urea nitrogen may be caused by renal failure, low blood pressure and high protein diet. Urea nitrogen is the product of protein metabolism. Its normal value is generally 2.5~7.5 mmol/L, and it is called as increase when it exceeds 7.5. If the patient has renal failure, the detoxification ability of the kidney will decrease, and urea nitrogen will naturally increase, which is generally accompanied by an increase in serum creatinine. Some patients also have high urea nitrogen due to vomiting, diarrhea or sweating, insufficient effective blood volume, decreased blood pressure, and insufficient renal perfusion. In addition, some patients had a high protein diet before checking renal function, such as eating a lot of eggs, drinking a lot of milk, eating a lot of bean products, and forming urea nitrogen after transformation in the body, which will also lead to high urea nitrogen.
