Whether or not creatinine of 35 μmol/L is serious depends largely on the cause of the low level. If the low creatinine is due to physiologic causes such as malnutrition or low muscle mass, it is usually not serious. If the low creatinine is due to pathological causes such as leukemia, tumors and other wasting diseases, it is more serious. Normal serum creatinine ranges from 53 to 106 μmoI/L in men and from 44 to 97 μmoI/L in women, with creatinine of 35 μmol/L being on the low side. It can be seen in physiologic and pathologic causes. Physiologic causes such as malnutrition, which may be related to daily picky eating, resulting in too little meat intake, or too little muscle mass, such as thin body type, the elderly and other low muscle mass, may appear creatinine lower than normal value. Combined with urine routine and urinary ultrasound and other related examinations do not see kidney disease, or improve the lifestyle creatinine may return to normal, this is usually not serious. If the low creatinine is caused by pathological reasons such as leukemia, tumor and other wasting diseases, it is more serious. There may be other reasons for the decrease of creatinine, it is recommended that patients go to regular hospitals in time, improve the examination to clarify the cause of the disease, and then give targeted treatment or therapy under the guidance of the doctor.