Definition: The gold standard, in terms of testing, is the test that most accurately determines the presence of a disease. It may not actually be used in a clinical setting, because of expense, time, degree if invasiveness or expertise, but it is used to determine the sensitivity and specificity of other tests. However, it is important to realize that most times, not even the gold standard is perfect. Therefore there is some ambiguity to those test characteristics.
In general, "gold standard" refers to the best available means of doing something. For example, randomized controlled trials are the gold standard of drug testing because they are the best way to determine if a drug is effective.
The "gold standard" refers to the most validated test that makes a diagnosis. The new test is compared to the most accurate test in use at the time.
Examples: Culture is currently the gold standard for chlamydia testing, because even though it will miss some cases of chlamydia (false negative) it will never find a case that isn't there (false positive)
