We have had many questions from our patients about COVID-19 testing and would like to shed some light to help you navigate this emerging market and understand what is available. Some questions we have been asked include:
- What tests are available for COVID-19 detection?
- Where is testing being offered?
- How accurate are the results?
- How long does it take to get results?
- Do you offer tests in your office?
- If I have a positive result, do I have immunity and how will it protect me?
What tests are available for COVID-19 detection?
All tests are not equal. Let me start by explaining how we have come to a conclusion about what deems one test better than another. Currently there are some tests available that have been through a verification process through the FDA using the fast track Emergency Use Authorization Act (EUA) and many more tests that have not been through any verification.
The test manufacturers and laboratories that are EUA approved for Coronavirus testing do not undergo the same rigorous testing that is required under non-pandemic circumstances. However, they are FDA authorized. All other manufacturers and labs are either pending EUA approval or have no outside validation.
The three types of available tests
There are certain tests available to hospitalized patients, and I will not be addressing those. I will, however, explain the three types available to the public and their utility:
- Nasal Swab (PCR or Molecular) Testing
- Stool Sample (PCR) Testing
- Antibody (Serology) Testing
Nasal Swab (PCR or Molecular) Testing
When someone is exhibiting symptoms related to COVID-19, a nasal swab is used for collection. The technical term for this test is called reverse transcriptase polymerase chain reaction (RT-PCR). The test looks to find specific viral particles, replicate them if present, and offers a result. A positive or negative result is provided.
These tests are about 70% accurate, with highest accuracy rates within the first 3 days of symptoms. Therefore, up to 30% of these tests produce false negative results. That means that up to 30% of the time an individual who is infected with COVID-19 will test negative, despite having the virus. (See reference)
Standard laboratory tests currently take 24-48 hours for results.
Rapid tests have emerged for point-of-care testing and these tests can produce results within 15 minutes. These rapid tests are similar to the rapid flu or strep testing we offer at our office. Currently, these tests are primarily being offered at drive through testing sites and Urgent Care Centers. We will most likely have them at Mindful Pediatrics once they become available.
Stool Sample (PCR) Testing
Stool samples are collected and tested using the PCR method, as mentioned above. These tests can be positive within a few days after the virus presents and linger in the intestine for an average of 27 days. Of those who tested positive using nasal swab, only 55% had positive fecal tests. This test is not very accurate in comparison to antibody (serology) testing discussed next. (See reference)
Antibody (Serology) Testing
Antibodies are created in our blood after our body has seen a virus. The body mounts an immune response, or attack, to protect the body from the invading pathogen. A blood sample is taken either through a finger prick or blood draw.
The technical term for the test is enzyme-linked immunosorbent assay (ELISA). The test uses a portion of the virus to draw out antibodies in the blood if present. Results usually return within 72 hours. If the test is done in the appropriate time frame, as described below, these results are extremely accurate.
One such antibody is called immunoglobulin M (IgM). This antibody is produced within the first week and remains positive for about two weeks. After this point, it no longer is detectable. Positive results can occur in those with symptoms and those without, but either way it is generally considered an active infection. For example, if you were to test an individual living with someone who tested positive for COVID-19, it is possible they too could have a positive IgM test for COVID (and therefore, an active infection) despite not having symptoms.
Another antibody is called immunoglobulin G (IgG). This antibody can take up to four weeks to develop and will remain positive for an extended period of time. It is these IgG antibodies that generally give us long term immunity to infections. It is not known for how long the SARS-CoV-2 IgG antibodies will remain. In contrast, for example, chicken pox IgG antibodies remain for a lifetime.
IgG antibodies can be detected in both those people who experienced COVID symptoms and those who did not. This test is most useful in the determination of whether or not someone has been infected. It is recommended to wait at least four weeks from the time of symptom onset.
For those who may have been asymptomatic, IgG testing is also an option for determining whether they unknowingly came into contact with the virus. We do, however, recommend ordering both an IgM and IgG for improved accuracy if you have not experienced COVID-19 symptoms. This test combining both antibodies is about 90% accurate. (See reference)
Do you offer testing at Mindful Pediatrics?
Mindful Pediatrics does not currently offer in-office testing. We will update you as soon as this becomes available.
If you and your family desire testing, we would be happy to schedule a short appointment for you. During this appointment, we will help you to find the appropriate location, write the necessary lab orders and we will provide the results when they are returned. If further interpretation of your results is needed, you will be able to schedule another short appointment so that we can discuss your results in greater detail.
Where is testing being offered?
The following organizations are those where we currently feel the most comfortable sending our patients because they are using EUA verified tests. As best you are able, determine which test the facility is using before you go.
For Nasal Swab Testing
As of the writing of this post on April 27th, there are currently 41 nasal swab tests that are EUA approved.
The Children’s Hospital Colorado in Denver is offering testing to patients and their caregivers, who are currently experiencing COVID symptoms, with a lab order from our office. An appointment is required. See this link for details.
For Antibody Testing
Currently, eight antibody tests have been EUA approved.
Boulder Community Hospital is currently offering antibody testing with a lab order from our office. No appointment is needed. Results are returned within 72 hours. Please contact BCH for hours, pricing and additional details.
Quest Diagnostics is also offering antibody testing with a lab order from our office. Results should return in 48 hours. No appointment is needed. Refer to their website for hours of operation at each location.
LabCorp is offering antibody testing with a lab order from our office. They are providing both an IgM and an IgG option. No appointment is needed. Please see their website for hours, pricing and additional details.
National Jewish Health has an entire website devoted to their testing. No lab order is required. See this link for details.
If I have a positive COVID-19 test result, do I have immunity? How long will it last?
Very little is known currently. The World Health Organization made a statement last week, “There is currently no evidence that people who have recovered from COVID-19 and have antibodies are protected from a second infection.”
Not enough time has elapsed to collect data to determine what positive antibodies will mean for later exposure to the virus. Although in general, past viral infections (such as the flu) offer at least some temporary immunity.
As we navigate this next phase of life during COVID-19, please contact us and let us know how we can serve you.
Our hope is that you come away from reading this with a better understanding of what testing is available, when it is useful and what it can tell you. Most importantly, we want you to know we are here to support you and your family in any way we can!
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Hello Mindful Family Medicine Friends,
I just wanted to say a quick thank you for your latest blog post about COVID-19 testing by Ara Haupt.
I had been searching for exactly that information for quite some time and to find it all in one location from a source I trust (and delivered directly to my inbox) has been a very welcome surprise.
As you know, our family has not been coming to your office on a regular basis anymore but I am still getting your newsletter which I really enjoy.
I feel blessed to know that you guys are around as an option if we ever need it.
I hope you are all doing well in these challenging times.
Please continue your great work.
Thank you for this beautiful note! We are so glad that this information was helpful!