Molecular Diagnostics refers to in vitro diagnostic techniques based on detecting relevant biological markers. The most commonly used biological markers are DNA and RNA. Molecular tests can be used to determine germline genetic alterations that predispose individuals to certain diseases. This type of test normally only needs to be performed once in life. Molecular tests can also be used to determine an individual’s exposure to environmental assaults, including viral or bacterial infections and somatic mutations. This type of test is performed repeatedly. Two main techniques used in molecular diagnostics are polymerase chain reaction (PCR) and DNA sequencing. Molecular tests can be either qualitative or quantitative depending on the clinical application. Clinical molecular tests are regulated either by the Federal Drug Administration (FDA approved/cleared) or by the Clinical Laboratory Improvement Act (CLIA) (Laboratory developed tests).