The elderly should consider a number of diseases, including gastrointestinal diseases, as well as diabetes, hyperthyroidism, tuberculosis and tumors. The most common test for the elderly is diabetes screening, including fasting blood sugar, blood sugar two hours after meals, and glycated hemoglobin. Gastrointestinal diseases include malnutrition, chronic gastritis, absorption dysfunction, pernicious anemia, etc. Gastroscopy, routine blood, stool and occult blood tests are required. The most common cause of wasting is also hyperthyroidism, which can be directly diagnosed by a feasible thyroid function test. Other screening tests include tuberculosis and tumor screening. The most commonly done tests for tuberculosis are the spot test and the Mycobacterium tuberculosis test; for tumor screening, the most basic test is the tumor marker test. In the case of elderly people who have lost weight, it is important to look at how many kilograms they have lost over a long period of time, whether they have lost food, or have chronic diarrhea, and then do some targeted tests based on the symptoms.