Blood creatinine is generally considered as endogenous blood creatinine, which is the product of human muscle metabolism. In muscle, creatine slowly forms creatinine mainly through irreversible non-enzymatic dehydration reaction, and then it is released into the blood and excreted with urine. Therefore, serum creatinine is closely related to the total muscle mass in the body and is not easily affected by diet. Creatinine is a small molecular substance, which can be filtered by renal glomerulus and rarely absorbed by renal tubules. Creatinine produced in the body is excreted with urine almost every day, and is generally not affected by urine volume. Clinical detection of serum creatinine is one of the main methods commonly used to understand renal function.

Guiding opinions:

After the creatinine produced by muscle metabolism in the body is released into the blood, it is blood creatinine. Serum creatinine and creatinine clearance rate are not completely consistent, and creatinine clearance rate is more sensitive than blood creatinine. In the early stage of renal insufficiency (compensatory period), creatinine clearance rate decreased, while serum creatinine was normal. When the glomerular filtration rate drops to more than 50% of the normal value, the serum creatinine begins to rise rapidly, so when the serum creatinine is significantly higher than the normal value, it often indicates that the renal function has been seriously damaged. Because creatinine clearance rate is also affected by glomerular concentration function, serum creatinine is the most reliable indicator to reflect glomerular function when renal concentration function is impaired. The serum creatinine of normal men is 53- 106 gmol/L, and that of women is 44.2-97.2 gmol/L. Serum creatinine is increased: it is found in acromegaly, gigantism, diabetes, infection, eating meat, exercising, taking drugs (such as vitamin C, levodopa, methyldopa, etc. ), acute or chronic renal insufficiency.

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