Blood is drawn from a person either from his inner arm near the elbow or from the top of the hand. The blood is then sent to a laboratory where the serum is separated from the red blood cells. The serum can then be tested in a variety of ways to determine and detect infection. Once the infection is detected, the appropriate antibiotic can be prescribed.
Many different types of tests can be performed on blood serum based on the suspected illness or disease. A few of the more common tests include agglutination, which determines the clumping or massing of cells and how they react to antigens; complement fixation, which shows the presence of an antibody and allows the antibody to bind to the antigen to see how it reacts; and fluorescent antibodies, which shows the distribution of specific protein signatures left by antibodies under different lighting. Each antibody reacts to differently to different fluorescent frequencies.