The first one is that edema often appears in the eyelids, face or lower extremities, shin front, ankle and other parts of the body. If pressure on the above parts is depressed and it takes some time to return to normal, it is often edema. Secondly, patients with edema often have some combined causes, such as poor heart function, nephritis or renal failure, and some patients may have poor liver function or malnutrition, which are often judged as edema when the above patients have swelling. Thirdly, edema can be judged by using diuretics. If the urine volume of the patient increases after taking diuretics and there is a significant weight loss, the possibility of edema is considered to be higher.