Biochemical tests are tests that help in the identification and differentiation of bacteria based on their metabolic activities. Each bacteria utilizes certain compounds (such as carbohydrate, protein, organic compounds) depending upon the availability of enzymes or appropriate environmental conditions (availability or lack of oxygen).
The end product of such reactions can be detected either by pH changes or by using indicator chemicals. The end results of such metabolic reactions form the basis of identification and differentiation of bacteria either to genus or up to species level.