Antibody Testing for Covid-19 Available at Stitches and What it Means to You

By Dan Surdam, MD and Amy Surdam, FNP

4

May, 2020

COVID-19
Stitches
Testing

The Surdams own Stitches Acute Care Center in Cheyenne, Laramie, and Wellington and are advancing telemedicine with InstaClinics. Contact amy.surdam@stitchescare.com for more information.

During the past several months, your Stitches team has done everything in their power to make sure we have been on the leading edge of the pandemic in an effort to keep our communities as safe and healthy as possible.  We have made the decision to offer antibody testing and have been doing so for the past week with some remarkably interesting results.  We are still sorting through what the results really mean from a public health perspective.

What Are the Different COVID-19 Tests Being Offered?

When looking for evidence of an infection, we have two tests we can use.  The initial test released to the public was the molecular test where we collect a nasal swab and look for the virus’s RNA (part of the genetic code inside the outer protein covering of the virus).  This is the best test to see if there is an active infection. 

The second test is to look for antibodies and is collected through a blood draw.  Antibodies are produced by our immune system in response to an infection.  The presence of antibodies can be a sign of an active, recent, or past infection.  It is important to remember that it takes time for these antibodies to develop.  In the first 5-10 days of the infection, antibodies will show up in only about 50% of the patients tested, but waiting two weeks from symptom onset, the test is more than 95% accurate.

What Does the COVID-19 Antibody Test Tell Us?

Also known as the SARS-COV-2 AB, the test checks for presence of antibodies to this specific Coronavirus in our blood.  As above, these antibodies are in response to the COVID-19 infection which we start to see approximately 7 days after onset of the illness.

Which Antibodies Will Be Tested?

We are utilizing the Cellex qSARS-CoV-2 IgG/IgM rapid test (https://cellexcovid.com/). It will test for both the IgM and IgG antibody for COVID-19.  We usually see the IgM antibody show up first, usually within 7 to 14 days of the infection and can last for several months.  The IgG shows up a little later and tends to persist for over 6 months (and maybe years).  If you have the IgM antibody, this can mean you still have an active COVID-19 infection, or you have just gotten over the infection.  The IgG antibody usually indicates past infection. 

Who Can Get Tested?

Stitches is offering the molecular tests to both asymptomatic and symptomatic patients. We are also offering antibody testing to anyone who requests the test, and recommend it for those who either are asymptomatic but think you may have had the infection or have been ill for more than two weeks.  Also, if you are already in the clinic and for a completely different reason, we can offer this test to be done on-the-spot.

Where is the COVID-19 Antibody Test Done?

Stitches offers the blood test to patients at any of our locations.  Convenience for our patients is of upmost most importance, and since this requires a blood draw, we have found it more efficient to schedule an appointment. Simply call our office to schedule.  If you didn’t schedule an appointment, no big deal, we have extended hours and open on the weekends, walk in anytime we are open, and we will take care of you!

How Long Do the Results Take?

Expected turnaround time today is 4-7 business days.  Since this test is very new, this may change with time.  As soon as we receive the results we will call you to discuss the results. 

Is it FDA Approved?

We are utilizing the first test to receive Emergency Use Authorization (EUA) from the FDA.  No antibody testing has received the official stamp of approval from the FDA, but they have stated it may be used under the EUA premise. From the FDA, “Results from the antibody testing should not be used as the sole basis to diagnose or exclude SARS-CoV-2 infection or to inform infection status.  Positive results may be due to past or present infection with non-SARS-CoV-2 coronavirus strains, such as coronavirus HKU1, NL63, OC43, or 229E.”

Does Having COVID-19 Antibodies Mean Immunity?

We’re not sure.  First, there are test results that can be falsely positive.  This may be due to a cross-reaction with other non-SARS-CoV-2 coronavirus antibodies.  Secondly, the assumption that you cannot get COVID-19 twice is at best a scientific guess and not a proven fact yet.  More data will be needed to determine what immunity these antibodies convey.  We also don’t know how long they will last.  This is why we encourage everyone to have both the molecular test and the antibody test done to provide us with the most information possible.

Prevalence of COVID-19

Why test at all? This blood test is currently of utmost importance in estimating the prevalence of COVID-19 in the general US population.  By testing the presence of the antibodies, we will have a better understanding of approximate percent of the population who has already been exposed or had COVID-19 and recovered.  The information is vital to our public health for both prediction of when we may see herd immunity, as well as validation and interpretation of future serological tests.  If you have the IgG antibody, you may also be able to donate plasma to help patients who are actively fighting the disease.

Herd Immunity

We need population level antibody information (seroprevalence) in order to predict just when herd immunity may develop.  Generally speaking, 60% of a population being immune to the virus will act as a firewall slowing or stopping the virus from effectively spreading to the remaining 40% of the population who is still susceptible.  Actual numbers of course depend on the how infectious the disease really is.

How Much Does It Cost?

For COVID-19 related illness and testing, most insurance companies have stated they will cover the entire cost, including testing.  We will bill your insurance company for the office visit, and the private lab will bill your insurance company for the lab tests.  If you do not have insurance, at this time through the CARES act, the office visit and lab test will likely be covered while funding remains (if funding runs out from the Federal Government, you may receive a bill).