In vitro biocompatibility tests are less expensive ways to survey newly developed materials.
They simulate biological reactions to materials when they are placed on or into tissues of the
body. These tests are performed in a test tube, cell-culture dish, or otherwise outside of a
living organism in which cells or bacteria are generally placed in contact with a material. For
example, a strain of bacteria may be used to assess the ability of a material to cause
mutations (the Ames test). The advantages of in vitro biocompatibility tests are, being
experimentally controllable, repeatable, fast, relatively inexpensive and relatively simple.
Another major advantage is that these tests generally avoid the ethical and legal issues that
surround the use of animals and humans for testing. The primary disadvantage of in vitro
biocompatibility tests is their questionable clinical relevance.