The presence of low blood creatinine in nephrotic syndrome may be related to malnutrition, metabolic abnormalities and lack of body muscle. 1. Malnutrition: low blood creatinine can not represent impaired renal function. If patients consume less exogenous protein, the production of protein metabolite creatinine is reduced accordingly, and the serum creatinine level will be low. 2. Abnormal metabolism: due to disease or some factors can not intake protein, or protein metabolism disorder, will also make the body protein metabolite creatinine production is reduced accordingly, so as to reduce the serum creatinine content. 3. Lack of body muscle: low blood creatinine in nephrotic syndrome may also be caused by low muscle content in the body. It is suggested that patients should consult the hospital in time to find out the cause and follow the doctor’s instructions to standardize the treatment.