The CDC HIV testing process includes initial blood screening, confirmatory testing, and improvement of related examinations. 1. Initial Blood Screening: The initial screening of the blood is done first, and generally the initial screening detects HIV antibodies. (1) If the result of the initial screening is positive, further confirmatory tests are needed; (2) If the result of the initial screening is negative, it is necessary to judge the need for subsequent retesting according to the time of the initial screening under the guidance of the doctor. If the initial screening is conducted after the end of the window period, and the initial screening result is negative, generally do not need to review; but if the initial screening is conducted within the window period, generally need to review. 2. Confirmatory test: i.e., this blood sample is used to re-do the test again, and generally there is no need to come back to the site for re-collection of blood. 3. Improvement of relevant tests: If the result of the above confirmatory test is also positive, you will usually be called to come back to the venue to improve the relevant tests for follow-up.