Normal cystatin C does not confirm normal kidneys. Cystatin C is an endogenous marker of glomerular filtration rate change, which mainly reflects whether the glomerular filtration function is normal. To determine whether the kidneys are normal or not, it is necessary to combine with relevant examinations such as urine routine, blood routine, urological ultrasound, CT, MRI, etc.; in addition, it is also based on the patient’s clinical symptoms, such as whether there are oedema, urinary frequency, urinary urgency, urinary pain, urinary abnormalities and other manifestations. Normal cystatin C usually indicates normal glomerular filtration rate, but it cannot exclude the existence of other renal diseases such as renal tubules, renal capsule structural and functional abnormalities, such as renal tubular acidosis and other diseases may also appear normal cystatin C. Therefore, normal cystatin C is not a good indicator of the presence of other diseases in the kidney. Therefore, normal cystatin C does not prove that the kidneys are normal. Whether the kidneys are normal or not needs to be judged by relevant examinations and clinical manifestations under the guidance of professional doctors, and it is recommended that patients should seek medical treatment in time and follow the doctor’s instructions.