Renal cyst is a general term for a cystic lesion in the kidney that is not connected to the outside world, and the examination is usually most extensive with ultrasound and CT. First of all, we can do routine urine examination, mainly to see whether there is infection in the cyst or kidney parenchyma, so it may be found mainly white blood cells in the routine urine, but also can be accompanied by some small amount of red blood cells. Next is ultrasound, which will clearly see the cystic stuff. This is a very convenient test to differentiate it from malignant kidney disease. Another test is renal venogram, which can show the degree of cyst compression on the kidney and can be differentiated from hydronephrosis. Another test is CT, which can determine whether there is bleeding and infection in the cyst and can show the characteristics of the cyst, as compared to ultrasound. Therefore, if CT is done, cyst puncture can be unnecessary in some cases. Patients who have this disease need to be given detailed and specific arrangements by your clinician.