Blood tests are samples of blood that are taken, typically from the jugular vein in the neck and analysed by a variety of different methods. There are two main types of blood test the first is where the actual constituents of the blood are examined i.e. the cells and proteins present. The second type of blood test that is performed is the biochemistry test which looks for different chemicals present in the blood. Blood tests are also used to identify the presence of antibodies as well as viruses and bacteria.