HIV testing is used to determine if you are infected with the human immunodeficiency virus (HIV). HIV is a virus that weakens your body’s immune system, making it difficult to fight infections and certain cancers. If HIV is not treated, you will eventually become very ill and may die. HIV testing can be done easily with a small sample of blood taken from a vein or even from saliva or a finger prick. These tests screen for antibodies that your immune system produces after being exposed to HIV. If the tests are positive, the result needs to be confirmed with further tests.