Urea usually refers to urea nitrogen and creatinine is blood creatinine. If urea nitrogen is 18.6mmol/L and creatinine is 164μmol/L, it is usually not serious and can be normalized after removing triggers and active treatment; if it is caused by chronic renal failure, it is relatively more serious, and it is necessary to follow the doctor’s instructions to improve the relevant examinations to make a clear diagnosis. Due to the different test standards in different hospitals, the specific reference value range also has some differences, it is recommended to interpret the report under the guidance of the doctor. The normal value of urea nitrogen is between 3.2~7.1mmol/L for adults and 1.8~6.5mmol/L for infants and young children; the normal value of blood creatinine is between 53~106umol/L for adult males and 44~97μmol/L for females. Urea nitrogen 18.6 mmol/L and creatinine 164 μmol/L can be caused by acute kidney injury, chronic renal failure and other factors. If it is caused by acute kidney injury, it is usually not serious, and can be normalized after removing the causative factors and active treatment; if it is caused by chronic renal failure, it is relatively more serious, and need to follow the doctor’s instructions to improve the relevant examinations to clarify the diagnosis, and actively standardize the treatment. If the urea and creatinine are found to be elevated, it is recommended to consult a doctor in time and follow the doctor’s instructions.