Description from the website: This virtual laboratory will demonstrate how such a test, termed an enzyme-linked immunosorbent assay (ELISA), is carried out and show some of the key experimental problems that may be encountered. Components of the immune system called antibodies are found in the liquid portion of blood and help protect the body from harm. Antibodies can also be used outside the body in a laboratory-based assay to help diagnose disease caused by malfunctions of the immune system or by infections. Some features of this virtual lab: 1. You don't need to complete the lab. The next time you enter the lab, you can choose to either "start over" or to "go to my last step". 2. You can use "go back" tab to review previous steps, "jump ahead" to see the following procedures. Also, you can "restart step" to practice the same step again. 4. Read "Laboratory Notebook" to learn why and how to do this experiment. The "Laboratory Notebook" helps you understand the meaning of this experiment. 5. A cool feature of this virtual lab is that if you make a mistake in some steps, like you set up the wrong time or wrong temperature for a reaction, the program won't alert you, just like in doing a real experiment, no one will tell you that you are doing something wrong. However, your wrong steps will lead to wrong results. In the end, the virtual lab will show what steps you did wrong. You should discuss why the wrong steps lead to the wrong results with your instructor or your classmate. More virtual labs can be found from the website: http://www.hhmi.org:80/biointeractive/vlabs/index.html