High cystatin C may be a normal physiological phenomenon, usually with no specific pathological symptoms, but it may also indicate certain kidney diseases, which are usually manifested by abnormal urine tests and symptoms such as swelling of the face or both lower limbs, fatigue and loss of appetite. It is recommended to go to the hospital to clarify the cause of the disease. 1. Normal physiological phenomenon: cystatin c is serum cystatin, which is an important indicator reflecting the function of human kidneys and may be elevated due to physiological reasons, and this phenomenon is mostly seen in people over 60 years of age, and there is no obvious discomfort in general. 2. Symptoms of kidney disease: high serum cystatin C can indicate a decrease in glomerular filtration function, which is one of the manifestations of early damage to the kidneys, and may be associated with certain renal diseases, such as chronic renal failure, diabetic nephropathy, chronic and acute glomerulonephritis, etc., and may be accompanied by urinary anomalies, double lower limb edema, or fatigue, loss of appetite and other symptoms. It is recommended that patients under the guidance of a professional doctor to carry out a scientific and comprehensive examination to clarify the cause of the disease, and then symptomatic treatment.