Molecular diagnostic testing uses sensitive and specific clinical laboratory techniques to detect and identify biomarkers at the most basic level, that of nucleic acids (DNA and RNA). Common applications of molecular methods include medical diagnosis, establishing prognosis, monitoring the course of disease, and selecting optimal therapies. Molecular methods are also used in both forensic and non-forensic identification. A variety of biological materials can be used for molecular testing including fetal cells from amniotic fluid, dried blood spots from newborn screening programs, blood samples, buccal (mouth) swabs, bone, and hair follicles.
Molecular diagnostic tests are increasingly used in many major areas of medicine including genetic disorders, infectious diseases, cancer, pharmacogenetics and identity testing. Examples include:
- Genetic disorders: Molecular methods are used to detect common inherited diseases such as cystic fibrosis, hemochromatosis, and fragile X syndrome.
- Infectious diseases: Many diseases including hepatitis, tuberculosis, human immunodeficiency virus (HIV), human papilloma virus (HPV), Chlamydia, Neisseria gonorrhoeae, and methicillin-resistant Staphylococcus aureus (MRSA) can all be identified faster and more accurately using molecular techniques as compared to traditional culture or antibody assays.
- Cancer: Some leukemias and solid tumor cancers can be detected and identified by molecular probes which target the abnormal gene rearrangements occurring in these disorders.
- Pharmacogenetics. Molecular testing can be used to individualize a specific dosing schedule for patients on a common blood thinner, warfarin, and thereby reduce the likelihood of overmedication and potential bleeding problems.
- Identity testing: Molecular diagnostic tests are used in determining the identity of combat casualties, in analyzing crime scene evidence, in determining paternity, and identifying foreign DNA in transplantation medicine.
These examples are only a small sample of the many clinical and other applications of molecular testing methods.
Molecular diagnostic scientists work in a variety of settings, including:
- Reference laboratories
- Law enforcement agencies
- Public health departments
- Research institutions
- Pharmaceutical companies
Most molecular diagnostic scientists have a baccalaureate degree and specialized training. Many laboratories doing molecular testing report that they have difficulty finding adequate personnel to fill current employment positions. The number of molecular-based laboratory tests is expected to increase dramatically as more is learned about the human genome and disease. It is predicted that the future will bring an even greater need for scientists in this dynamic field.
Here are the words of a recent graduate who has a baccalaureate degree in clinical laboratory science from UNC-Chapel Hill and advanced training in molecular diagnostic science:
"I currently work as a Forensic Biologist in a crime laboratory. We assist law enforcement investigations by identifying contributors of samples that are left at crime scenes. The evidence is analyzed first to determine the type of body fluid that is present. The DNA found in the body fluid is then extracted, quantitated, amplified, and electrophoresed. The end product of this process is a genetic profile. By looking at several different areas of an individual's DNA, we are able to ensure that the sample is unique. We are also responsible for a DNA Database that contains the genetic profiles of all individuals charged with a felony in the state. This database is used to link cases together and to solve cases in which no suspect has been identified. I thoroughly enjoy my career because this work implicates the guilty and exonerates the innocent. DNA is not biased. I feel that I can give a voice to those who cannot speak for themselves and provide closure for families. I can give rape victims a sense of security when their attacker is finally convicted of his crime. I am also able to free those who have been wrongly accused. I cannot imagine a better career for myself."
Additional career information about molecular diagnostic science can be found at these websites:
- Association for Molecular Pathology: http://www.amp.org/
- American Society for Clinical Laboratory Science: http://www.ascls.org/