Urinary creatinine and blood creatinine are not the same and represent different meanings. Urinary creatinine reflects the excretion of creatinine in urine, and urinary creatinine is often used to evaluate the excretion of urinary albumin. Clinically, urine creatinine is mainly used together with serum creatinine to explain glomerular filtration function, and measurement of urine creatinine alone has little significance in renal dysfunction. Serum creatinine is the amount of creatinine in the serum. Excluding physiological causes such as excessive protein intake or strenuous exercise that result in elevated serum creatinine, it can be used clinically to indicate impaired renal function, such as reduced glomerular filtration rate. Serum creatinine is mainly used clinically to evaluate glomerular filtration function. When there is an abnormality in the experimental test, it is recommended to follow the doctor’s instructions to conduct further relevant examinations, clarify the cause with the help of the doctor, and carry out standardized treatment.