What's the matter with the high urea nitrogen to creatinine ratio

Urea nitrogen is one of the main indicators of renal function, while creatinine is the metabolic product of muscle in the human body. Many people don’t know why the ratio of urea nitrogen to creatinine is high. Generally speaking, disease factors will cause the ratio of the two to increase, such as nephritis.

1. Under normal circumstances, the ratio of blood urea nitrogen to creatinine (BUN/Scr) is about 10. A high-protein diet, high catabolic state, dehydration, renal ischemia, insufficient blood volume and certain acute glomerulonephritis can increase this ratio, even to 20-30; a low-protein diet and liver disease often lower the ratio, which is called hypoazotemia. An increase in the urea nitrogen to creatinine ratio indicates that the kidney function has been damaged and the glomerular filtration rate is abnormal, so the patient is receiving traditional Chinese medicine treatment to repair the damaged kidney function.

2. It is more meaningful to measure urea nitrogen and creatinine at the same time. If both of them increase at the same time, it indicates that the kidneys are seriously damaged. When the renal glomerular filtration rate drops to 1/2~1/3 of the normal level, urea nitrogen gradually increases. Under normal circumstances, the ratio of blood urea nitrogen to blood creatinine is 10.1. The reasons for the high ratio include gastrointestinal bleeding, hemolysis, heart failure and enhanced tissue decomposition (burns, high fever, adrenal cortex hormone treatment, etc.), which are mostly caused by prerenal factors. A decreased ratio is seen in insufficient protein intake, severe liver and kidney dysfunction, etc.

3. The main reason for high urea nitrogen is that blood urea nitrogen is easily affected by urine volume and nitrogen load. For example, upper gastrointestinal bleeding, certain serious liver diseases, severe infections, the use of adrenal corticosteroids and excessive protein in the diet can cause a temporary increase in blood urea nitrogen. In addition, in the early stage of renal insufficiency, blood urea nitrogen may not increase. Only when the glomerular filtration rate drops below 50% of the normal level, blood urea nitrogen will show abnormalities. Therefore, if urea nitrogen is high in the renal function test, do not ignore it or be too nervous. Although blood urea nitrogen can be used as an indicator to judge glomerular function, it is not as accurate as blood creatinine in clinical practice. Therefore, it is necessary to correctly judge the cause of high urea nitrogen. In order to timely exclude the possibility of kidney disease, it is recommended to do a systematic examination such as B-ultrasound, urine routine, blood routine, etc., to clarify the real cause of high urea nitrogen and treat it in time.