Doctor looking at handheld screen showing DNA and disease information

Methods of Detecting COVID-19

It seems like eons ago that the nation saw its first cases of COVID-19. In the early stages of the outbreak, the coronavirus was all anyone could talk about. Questions like, “How infectious is it?”, “What are the symptoms?”, and, “Who is at risk?” were at the forefront of our thoughts and conversations. 

 

As time and research have answered many of those once-elusive questions, we’ve settled into a new normal with several methods of testing that mere months ago weren’t available. The existing and emerging methods of testing are becoming faster and more accurate than before.

 

In this article, you’ll learn all of your options for getting tested, how the different tests work, which ones give you the most accurate coronavirus diagnosis, and what kinds of tests may be possible in the future.

 

Diagnostic vs. Antibody Testing

The two broadest testing categories are diagnostic and antibody testing. The main difference between them is that diagnostic tests provide a current coronavirus diagnosis while antibody tests can only show if you’ve had the virus in the past. These tests are described in greater detail below.

 

Diagnostic Tests

Molecular testing is the most effective and common way to diagnose COVID-19. These tests identify the genetic material of the virus in the patient’s nose or throat. They can be done with a throat or nasal swab (and, in some cases, a saliva sample) and produce results in one day to one week. Molecular tests go by several other names, including viral tests, nucleic acid amplification tests (also known as NAAT tests), and RT-PCR tests

 

When you take a diagnostic molecular test, the steps are as follows:

  1. A health care professional inserts a sterile swab into your nose or throat and collects enough mucus for NAAT testing.
  2. The swab test is transferred to an uncontaminated container, held at a specific temperature to keep the virus alive, and taken to a lab within 72 hours for a polymerase chain reaction test (PCR testing).
  3. The genetic material from the virus is extracted from the swab using primers and probes — a special chemical mix. Then, the genetic material is copied using a machine that heats and cools it, turning it into DNA that can be made into millions of copies.
  4. If the person is infected, the DNA will be bound to certain probes, which is visible when a special light is shined on it.

 

While molecular testing detects the genetic material of the virus, antigen testing (also known as a rapid diagnostic test or a rapid antigen test) looks for specific proteins that are known to reside on the surface of the virus. Unlike molecular tests, these antigen tests can be performed quickly in a doctor’s office — but with a high chance of false negatives. 

 

In most setups, the process follows these steps:

  1. A nasal or throat swab test is done to collect mucus or other bodily fluids.
  2. The bodily fluid is mixed with a buffer solution, which is then dripped onto a test strip over antibodies for the viral protein. 
  3. If the antibodies detect the protein, the test strip will change color and indicate a positive test result.

Doctor looking at digital model of a virus

Antibody Tests

Antibody tests, otherwise known as serology tests, are very distinct from diagnostic tests. They look for the presence of antibodies in the blood to determine whether or not a person’s immune system has fought the infection before. Antibody tests can produce results in one to three days but may sometimes require a second test to verify accuracy.

 

Antibodies are the proteins responsible for fighting infection and building immunity — but researchers aren’t yet sure if antibodies could protect you from another coronavirus infection. 

 

The process for antibody testing is simple. A health care professional will stick your finger and collect a sample of blood to look for IgM antibodies, which appear in the early stages of infection, and IgG antibodies, which come later. The presence of these antibodies could mean that you’re still contagious or that the virus has already run its course.

 

COVID-19 Test Methods and Where to Take Them

 

There are several options for taking these tests, and they include:

  • At-home sample collection: If you are unable to leave your home for a COVID test, your doctor may prescribe you a test that allows you to collect your own sample and send it to the lab. Speak to your primary care physician for more information.
  • Saliva tests: Nasal swabs are quite invasive for the patient and are considerably more risky for the person conducting the test at close proximity to the potentially infected individual. Now, there are saliva tests that allow you to spit in a tube for your comfort as well as the safety of health care workers.
  • Point-of-care (POC) testing: If you want to know your results quickly, POC molecular and antigen tests give you a diagnosis within mere minutes so you can take action sooner if you get a positive result. These tests are administered in doctor’s offices, drive-up testing locations, pharmacies, urgent care clinics, school health clinics, and long-term care facilities and analyzed at medical clinics.

 

Future Testing Method Possibilities

As science learns more about COVID-19, researchers have continued to discover new and exciting ways to test for the virus. Take the development of the SARS-CoV-2 RapidPlex at Caltech, for example. This machine was built to address the issue of asymptomatic carriers spreading the virus unknowingly while waiting days for their test result. The RapidPlex is an at-home sensor that can detect the virus within 10 minutes with a mere drop of saliva or blood, eliminating the long wait time and the uncertainty. Read more about how it works here.

 

Another exciting development is the combination of transcription/translation technology (TXTL) and toehold switches, which together can detect COVID’s nucleic acid sequences within POC devices. This diagnostic method utilizes synthetic riboregulators to detect the presence of SARS-CoV-2 genes. Riboregulators respond to a target RNA by turning off gene expression, and the output is a fluorescent protein. You can learn more about this test here.

 

These simplistic, low-cost tests could open up a world of possibility for COVID-19 tests and potentially slow the transmission of the infection.

 

How Psomagen Tests for COVID-19

Psomagen prides itself on sophisticated in-vitro lab-developed tests (LDT) that use RT-PCR to accurately detect COVID in bodily samples. Our FDA emergency use apporval (EUA) test is a fast, reliable, easy four-step process that any CLIA-certified laboratory can administer in-house under the condition that you disclose results to public health authorities.

 

Our tests have shown to be 100% consistent in clinical trials, and you can provide results to patients may be up to 24 hours. Request a quote from us today!