In what ways do forensic scientists protect the reliability and sensitivity of their evidence?

The evidence is tested repeatidly to ensure it produces the same results of idenitifcation and comparison. If the same result is produced, it is considered reliable. A test must be sensitive in the sense that it identifies the unique characteristics of the sample. For example, a DNA test can identify people based on their unique DNA. Finally, tests are specific if they identify particular substances. A test would be specific if it identified the presence of a particular drug, like cocaine, with no other drugs giving the same result.