What is Molecular Testing?

In the age of COVID, although on what appears to be a downswing, the rise of PCR and at-home test kits have become the go-to methods for testing. While these test options are not new per se, their use has taken the world by storm.

These consumer-facing diagnostic tests fall under the molecular diagnostics category of testing. Also referred to as molecular pathology, these tests analyze a patient’s DNA or RNA sequences for the potential emergence of disease.

According to the CDC, “Molecular diagnostic testing combines laboratory testing with the precision of molecular biology and has revolutionized the way clinical and public health laboratories investigate the human, viral, and microbial genomes, their genes, and the products they encode.”

Examples of Molecular Testing

Molecular tests are performed to determine if a person has a specific disease (i.e., COVID). Additionally, these tests can help determine whether or not patients have a gene mutation associated with a particular disease in various stages of life (prenatal, newborn, adult, etc.). These tests are used in many areas of medicine including oncology, infectious diseases, clinical chemistry, and clinical genetics.

For example, according to Yale Medicine, a common inherited disease is cystic fibrosis (CF). If a newborn is found to have two mutations in the gene associated with CF, the baby is most likely to have the condition. The child can be treated for the disease based on the diagnosis. Another example is a molecular test for hereditary cancer, and the BRCA1 and BRCA2 genes. These inherited mutations may increase the patient’s risk of developing breast and ovarian cancer.

Molecular Tests and COVID

With COVID, the FDA granted emergency use authorization (EUA) for various testing methods to detect and diagnose COVID-19, including a molecular option. A polymerase chain reaction (PCR) test is performed by a healthcare professional who inserts a nasal swab into a patient’s nostril to collect the specimen. Once collected, the fluid is analyzed to determine if the patient has the genetic material (RNA) of SARS-CoV-2, the virus that causes COVID-19.

According to the Cleveland Clinic, scientists use PCR technology to amplify small amounts of RNA from specimens into deoxyribonucleic acid (DNA), which is replicated until SARS-CoV-2 is detectable if present. This has been the gold standard of COVID testing for nearly three years.

PCR tests have been almost synonymous with COVID testing, but this is a method used for more than just pandemic reasons. These tests are a fast, highly accurate way to diagnose infectious diseases and genetic changes. Unlike many other tests, PCRs can find evidence of disease in the earliest stages of infection when there is only a very small amount of pathogens in a patient’s body.

As it relates to COVID testing, these PCR tests use a nasal swab as the specimen collection method. However, these tests can also be performed using a blood draw. Depending on what the test is analyzing, the specimen collection method may differ.

While PCR and at-home rapid COVID tests (antigen) both require specimen collection via nasal swab, their use differs. Each test detects a different part of the virus. Antigen tests may be much faster, but they are far less accurate. These tests use lab-made antibodies to search for antigens (substances that cause the body to produce an immune response) from the SARS-CoV-2 virus.

The Future of Molecular Testing

The general population might not have been familiar with molecular testing prior to the onset of the COVID-19 pandemic a few years ago. Now, most people likely either know someone who has had a PCR test or have had one themselves. Molecular testing options are an important diagnostic tool that can help determine a patient’s course of treatment and shed light on what is going on with their health.

Molecular tests, such as a nucleic acid amplification test (NAAT), can provide labs with accurate and timely results compared to other testing methods, such as a culture. Quicker and more accurate results mean providers can optimize their patient’s treatment plans and improve health outcomes.

As the testing world returns to its “normal” state, molecular testing is sure to be more than just an option for COVID diagnosis.


**Medically reviewed by Dr. Sona Kirpekar, MD

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