Analysing the molecules within organs, tissues, and bodily fluid to diagnose diseases by identifying molecular and pathway alterations. Molecular pathology is used in diagnosing cancers and infectious diseases including SARs, influenza, Tuberculosis, etc.

Some examples of how molecular pathology can be used: Establishing the basis of an existing disorder (diagnostic testing), Determining the presence of a genetic condition when there are no obvious symptoms (predictive testing), Carrier testing, Assessing a fetus for abnormalities (prenatal testing), Detecting cancer-causing gene mutations, Selecting pharmacotherapy