Definition:
An in vitro test is a medical test, experiment, or procedure that is done outside of the body, such as in a test tube or laboratory dish.
This is in contrast to an "in vivo" test, one that is done in a living organism, such as a laboratory animal or in humans.
Most chemotherapy drugs for lung cancer are studied in vitro before they are tested in vivo.
Examples:
The results of in vitro tests with the new chemotherapy drug appear promising. So it will now be tested in vivo in a clinical trial.
