How do IgG and IgM Serology Tests Compare To RT-PCR and Other RNA Tests? Can They Help Stop the Spread?

How do IgG and IgM Serology Tests Compare To RT-PCR and Other RNA Tests? Can They Help Stop the Spread?

As serology (antibody) tests hit the USA market, people want to know the reliability of these tests and how they will help reduce the spread of COVID-19.

It’s a valid question which can be asked equally about any of the tests on the market currently approved by the FDA.

The Wall Street Journal reported this past Friday (Section A7) on the mounting anecdotal evidence questioning the reliability of the “gold standard” RT-PCR test.

More and more doctors and technicians are seeing the false negative rate hover around 30%.

Abbott Labs, maker of the highly touted Abbott ID NOW POC test, which was prominently featured at a Rose Garden press conference, refuses to disclose the reliability of their 5-minute test.

Below is a screen shot of the canned response Abbott was offering on LinkedIN to all who queried about their new test:

Fox News contributor Dr. Marc Seigel spoke with Adm. (Dr.) Brett Giroir, assistant secretary of Health and Human Services (HHS) about the Abbott test and noted: 

“Giroir told me he thinks the Abbott test is relatively accurate.”

Indeed, part of what is making containment of this novel Coronavirus so difficult are the prevalence of false negative tests.

In some ways, an antibody test is superior than a viral RNA test due to the simplicity of the test and the absence of contamination risk; like what recently happened to a batch of probes and primers headed to the UK.

It's true that an antibody test can also delivery a false negative if administered too early, but the degree of accuracy on positive results, at least for the test we offer, is nearly 98% when compared with similar RT-PCR tests: 

If the patient has IgM antibodies – the patient is infected with SARS-CoV-2.

Additionally, in terms of producing a better statistical pool to capture the true scope of the virus, antibody tests can quickly identify asymptomatic, yet infected and those who have moved into the recovery phase, indicated by the presence of IgG antibody.

The New York Times reports Britain, Italy and others are directing significant attention to the IgG antibody question looking for clues to tell when a patient has fully recovered and can now be declared immune.

This has enormous workplace implications and relevance to hospitals exploring plasma transfusions for those most sickened by the virus.

It remains to be seen whether an “immunity passport”, as Britain and Italy are contemplating, is the way forward or just the first of many ideas towards reintegrating into society.

At some point though, it will be the presence of antibodies that will allow for life to resume some normalcy.

With the clock ticking ever closer to midnight, its time we take advantage of all the weapons at our disposal, flawed as they may be.

Better a dull sword to slay the dragon than no sword at all.