Bioluminescent organisms are a target for many areas of research. Luciferase systems are widely used in the field of genetic engineering. They have also been used in biomedical research, to give some cells visible labels. Luciferin can be added to molecules and cells to make them visible under the microscope. "This market is now worth about £20bn. If you go into a hospital and have a blood test which measures viral proteins, cancer proteins, hormones, vitamins, bacterial proteins, drugs, it will almost certainly use this technique".