The doctor will first weigh the patient and can determine the severity of the wasting. Combined with the patient’s general examination such as body temperature, blood pressure, skin mucosa and hair, this will help to detect diseases such as anaemia, tumours and chronic infections. Based on the results of laboratory tests such as routine blood, urine and faecal tests and biochemical and various hormonal tests, this will help to make a preliminary diagnosis of the cause of the disease, followed by imaging tests such as X-ray and endoscopy, which will gradually clarify the cause of the disease.