Patients with thalassemia can only be determined by genetic diagnosis of thalassemia, which cannot be seen with the naked eye, including by looking at the results of their tests. Many pregnant women will take their test results to the clinic and ask if they have thalassemia, and the doctor will not be able to give a definite answer. There are three steps to determine if a person is thalassemia: 1) a routine blood test; 2) if there is a decrease in the concentration and volume of red blood cells in the routine blood test, a thalassemia screening test will be recommended; 3) if there are abnormalities in the thalassemia screening test with specific indicators, the patient will then be recommended to do a genetic diagnosis, which is the final test to determine if the patient has thalassemia. If the child is born and grows into an adult, he or she may only be a mild or stationary or intermediate thalassemia patient, or a carrier. Therefore, it is necessary to analyze the results of routine blood tests, thalassemia screening test results and related clinical symptoms together, and finally the genetic diagnosis will determine the final diagnosis to know whether the patient is a carrier or a patient with thalassemia.