What you should know about testing for COVID-19 infections

Medical researchers continue working around the clock to improve on currently available tests and enable health providers to verify the presence or absence of the novel coronavirus as quickly and accurately as possible. Speedier test results will allow earlier isolation of infected persons and help curb the spread of the disease.

There are presently three different testing options for the novel coronavirus: 1) Antibody testing, which tells you if you’ve been infected in last four weeks; 2) Antigen testing, and 3) Polymerase Chain Reaction (PCR) testing, both of which can tell you if you have an active infection.

The PCR Assay is the most widely used test in the U.S. currently. Results can take six hours after the sample is received, but can take be greater than 24 hours depending on where the testing lab is in relation to where the sample was taken.

CDC-developed PCR test

The 2019-nCoV Real-Time Reverse Transcriptase (RT)-PCR Diagnostic Panel (see illustration) needs a specimen from the upper or lower respiratory system, which is retrieved with a nasal swab. This test takes added time since, once at the lab, the specimen needs to be processed.

The lab workers extract the virus’s RNA, the molecule that helps regulate genes. The step of the RNA extraction is also a limiting factor, as only the largest labs have automated ways of extracting RNA from a sample quickly.

After the RNA is extracted, technicians also must mix special chemicals with each sample and run those combinations in a machine for analysis, a process to perform a polymerase chain reaction. The result will reveal whether the sample is positive or negative for COVID.

Antigen test

Unlike a PCR test, which looks for genetic material related to the virus, an antigen test looks for virus protein, which the body detects as a foreign intrusion that triggers the immune system into action.

Antibody test

The CDC (Centers for Disease Control) is also working on developing its own serology (antibody) test related to the novel coronavirus, but this process requires a number of blood samples from confirmed COVID-19 patients. The FDA has approved an antibody based test by Cellex, This blood test may deliver a result within 15 minutes, but does require a specialized lab.

Abbott PCR test

Abbott labs has a point-of-care PCR test that has been granted emergency use authorization by the FDA. Time is saved, as the sample does not necessarily need to be shipped out, and the extraction is automated, thus saving tremendous time if a healthcare system has Abbott’s platform.

Initially, a major limitation was that facilities needed access to the Abbott m2000 real time system.  According to Abbott, it is in 175 U.S. hospitals and academic medical centers.

Fortunately, they refined the process to be compatible with ID NOW testing devices, which are about the size of a toaster. This sort of equipment can be deployed anywhere it’s needed, and can be operated without sophisticated training. The ID Now devices can provide a positive result within five minutes and a negative one in about 13 minutes.  Abbott states their platform can potentially accommodate 50,000 tests a day.

Mayo PCR test

The Mayo Clinic has also developed an automated PCR test that should provide results in 24 hours or less.

Sean J. Ennevor, M.D. graduated with a B.A.S. in biology and economics from Stanford University, and as a Dean’s Scholar from UCLA School of Medicine where he received his MD. He completed his medical residency and fellowship in anesthesiology at Yale University, where he was chief resident and on staff. He practiced medicine in the Twin Cities for over 14 years, and presently serves as an advisor and investor for medical technology companies throughout the country.