Molecular testing is a broad category of tests that look for molecules in your DNA or other pieces of genetic information called RNA to diagnose a disease like cancer or predict your risk of future diseases. These molecules might be
Molecular tests have replaced conventional tests in many fields of medicine. Some of their uses include:
- helping plan treatment
- finding out if treatment is working
- estimating your outlook
- predicting whether your cancer will come back or has spread
Read on to learn more about molecular testing, including how it works, its uses, and the different types.
Molecular testing is a field of diagnostic medicine that has undergone rapid development in recent years.
A molecular diagnostic test analyzes the genetic information in your DNA and RNA by examining a tissue sample to look for specific disease markers. The tissue sample might be:
- specific organ tissue
DNA comprises long strands of molecules that contain all your genetic information. DNA is in the nucleus of every cell in your body, and its structure resembles a twisted ladder. If a cell were a restaurant, DNA would be like the cookbook that contains all the restaurant’s recipes.
RNA is a strand of genetic material outside the nucleus that tells the functional structures in the cell what to do. Using the restaurant analogy, RNA is like a copy of an individual recipe in the cookbook that each restaurant cook receives.
A molecular test analyzes changes in these two types of molecules to look for red flags that might indicate a current or future disease.
Molecular testing has many uses. Here are just some of them.
Molecular testing for cancer
Molecular testing can identify genes with links to certain cancers. For example, mutations in the
Molecular tests can also help identify biomarkers that suggest that certain treatments might be more effective. For example, certain changes in the
Molecular testing for COVID-19
Molecular testing for COVID-19 involves using a technique called reverse transcription polymerase chain reaction (RT-PCR). This test can better inspect pieces of the SARS-CoV-2 virus to see if you have COVID-19. These tests are typically
Molecular HPV testing
Molecular human papillomavirus (HPV) tests involve analyzing pieces of viral DNA to see whether they contain HPV. There are a variety of tests available that scientists can use to check for HPV.
Molecular testing for disease markers
Genetic tests can look for mutations or variations in your DNA linked to the development of certain diseases. This is useful if you have genetic conditions running in your family to see if you inherited the genes. For example, inherited changes in the genes LDLR, APOB, and PCSK9 have links to familial hypercholesterolemia.
Other Infectious diseases
Scientists can use molecular tests to diagnose respiratory, gastrointestinal, and central nervous infections. Some tests can detect more than 20 infectious organisms, such as viruses or bacteria, in about an hour.
Molecular tests have many other purposes, including:
- tracing ancestry
- diagnosing other conditions like
- flu strands
neurological diseases, such as Alzheimer’s disease and Parkinson’s disease
- STDs like chlamydia and gonorrhoea
- screening newborns for genetic conditions
- forensic testing for identifying people for legal reasons
- testing for possible drug resistance in bacteria
The are several different types of molecular tests, such as:
Molecular PCR testing
A polymerase chain reaction (PCR) test is a specific type of molecular test used to amplify specific sections of DNA for a wide range of purposes, such as:
- diagnosing infectious diseases like COVID-19
- cloning genes
- prenatal screening tests for genetic irregularities
Kary B. Mullis developed the PCR method in the early
Other types of NAATs can help diagnose infectious diseases. Besides PCR,
- clustered regularly interspaced short palindromic repeats (CRISPR)
- helicase-dependent amplification (HDA)
- loop-mediated isothermal amplification (LAMP)
- nicking endonuclease amplification reaction (NEAR)
- strand displacement amplification (SDA)
- transcription-mediated amplification (TMA)
Rapid molecular testing
Rapid molecular tests can produce results very quickly. For example, molecular tests for influenza can detect upper respiratory tract infections in
Commercial at-home tests
Many types of molecular tests are now available as home tests where you can send the samples to a laboratory for analysis. Examples include home COVID-19 and ancestry genetic tests, such as 23andMe and AncestryDNA.
Antibiotic susceptibility testing
Doctors sometimes order antibiotic susceptibility testing to see which drugs will be the most effective, especially when drug-resistant organisms are prevalent.
Current testing techniques require 2 days to 1 week for results. While awaiting the results, the doctor will likely prescribe you the highest recommended antibiotic for your specific infection.
Genetic tests help identify changes in your genetic information linked to certain diseases. Types of genetic tests include:
- Targeted single variant tests: These tests look for one specific gene. For example, they can detect the HBB gene that determines sickle cell anemia.
- Single variant: Single variant tests look for a change in any one gene.
- Gene panel: A gene panel can identify changes in multiple genes.
- Whole genome sequencing. These tests examine most of your DNA to find gene variations linked to disease.
Providing a sample for a molecule test can be very quick. For example, receiving a nasal swab result for COVID-19 may take less than a minute. Most samples require laboratory analysis. The results of some tests are available in as little as an hour, while others might take 1 to 3 days.
Some rapid tests can provide results in as little as
The field of molecular diagnostic testing is growing rapidly. Its role in precision medicine will likely continue to grow.
In precision medicine, doctors use biomarkers to develop an individually tailored treatment plan for a disease. For example, two people with the same type of cancer might have different responses to the same treatment based on the presence or absence of certain gene mutations.
According to the
Promising research is underway examining how the microbiome in your gut influences your health and whether manipulating it can aid help with the diagnosis and treatment of disease.
Molecular testing will likely play an important role in the future development of treatments like fecal microbiota transplants. This treatment involves transplanting donated stool from one person to another to introduce beneficial bacteria.
Molecular testing includes a wide range of tests that look for biomarkers in the RNA and DNA of your cells. They have many applications, such as helping doctors diagnose infections or helping them choose the best treatment for a condition.
The field of molecular testing is rapidly growing and is likely to play an increasingly important role in medicine as more individually tailored disease treatments become mainstream.