High creatinine is a higher than normal creatinine value, and creatinine includes blood creatinine and urine creatinine, but blood creatinine is more meaningful than measuring kidney function, so high creatinine generally refers to high blood creatinine. Generally speaking, the normal value of blood creatinine is 44-133μmol/L. The causes of high creatinine include physiological factors such as strenuous exercise or overexertion, which leads to dehydration of the body, or excessive intake of purine, which causes a temporary increase in creatinine. In addition, pathological factors may also cause the blood creatinine value to rise, when the creatinine value is greater than 133μmol/L, it indicates that there is kidney damage, such as kidney disease, poisoning, myocardial infarction, muscle damage, hypertensive nephropathy, diabetic nephropathy, etc. Creatinine is a product of human muscle metabolism. In human muscles, creatine is formed slowly mainly through irreversible non-enzymatic dehydration reactions, and then released into the blood and excreted in the urine. The value of blood creatinine depends on the glomerular filtration rate in the kidney. When the kidney function is impaired, the glomerular filtration rate decreases, and the value of blood creatinine is high. It is common in the following cases: 1. Glomerulonephritis: both acute and chronic glomerulonephritis may lead to impaired glomerular function and restricted metabolite excretion, which leads to elevated blood creatinine; 2. Renal failure: both acute and chronic renal failure may have impaired kidney function and decreased endogenous creatinine clearance, and blood creatinine may be elevated. If renal failure is advanced, that is, when uremia occurs, the blood creatinine value is higher and can be greater than 445μmol/L; 3, other: the toxic effects of some foods or drugs lead to impaired kidney function, such as the improper use of gentamicin, tacrolimus, etc., there may also be high creatinine; or other acute and chronic diseases in the process of development, such as muscle damage, myocardial infarction, diabetic nephropathy, or other acute or chronic diseases in the process of development, such as muscle damage, myocardial infarction, diabetic nephropathy, hypertensive nephropathy, lupus nephritis, etc., which cause kidney cell damage or necrosis, thus leading to impaired kidney function and corresponding increase in creatinine level.