Hydronephrosis may cause elevated creatinine level, but there is also a possibility that creatinine level is normal, which is related to the degree of hydronephrosis.1. If the hydronephrosis is unilateral, even if the hydronephrosis is more than severe, the creatinine level can still be normal, as long as the parenchyma of opposite side of the kidneys is normal, there is no hydronephrosis, and the opposite side of the kidneys can metabolize the toxins in the body, which can then show normal creatinine. 2. If the hydronephrosis is bilateral, creatinine level may increase, and the more serious the degree of bilateral hydronephrosis is, the higher the possibility of abnormal creatinine level. Because bilateral hydronephrosis can lead to bilateral renal unit compression, over time, it is easy to lead to the lack of renal unit to cause further damage to renal function, then creatinine level can be increased.3. If congenital hydronephrosis occurs in the only kidney, it may lead to increased creatinine level, and it needs to be treated positively, and to protect the renal function will not have the corresponding damage or functional failure and other changes.