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COVID-19: Testing

By / Antibody, COVID, Diagnosis, Testing
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There are multiple tests available to help with diagnosis of the COVID-19 infection. I’d like to separate them into 2 categories:

  • Diagnostic Tests: Diagnose an acute infection
  • Antibody Tests (Serological Assays): Confirm a previous infection

Diagnostic tests detect the genetic material of the Coronavirus that causes COVID-19, so called real-time reverse transcription–polymerase chain reaction (rRT-PCR) assay, which allows detection of the virus during acute infection. The specimen could be collected using nasal swabs, or saliva samples. These tests are used in patients, who have symptoms suspicious for the COVID-19 infection. Most of these tests are done in hospitals or by special drive-thru testing. The results are available within 15 minutes up to 24 hours, depending where the test is done and what test is administered. Recently the FDA approved a home collection kit, which will be available to the public thru Labcorp within the coming weeks, and other similar tests will be available soon also.

According to the IDSA, the following patients should be considered the highest priority for diagnostic testing:

  • Patients who are critically ill or who have unexplained viral pneumonia or respiratory failure
  • Individuals with fever or signs/symptoms of a lower respiratory tract illness, who have had close contact with an individual with laboratory-confirmed COVID-19 within 14 days of symptom onset
  • Individuals with fever or signs/symptoms of lower respiratory tract illness who have traveled within 14 days of symptom onset to areas where sustained community transmission has been reported
  • Persons with fever or signs/symptoms of lower respiratory tract illness who are immuno-suppressed, are older, or have underlying chronic health issues
  • Persons with fever or signs/symptoms of lower respiratory tract illness who are critical for the pandemic response, including healthcare workers, public health officials, and other essential leaders

If you test positive for COVID-19:

If you test negative for COVID-19, you probably were not infected at the time your sample was collected. However, that does not mean you will not get sick. It is possible that you were very early in your infection when your sample was collected and that you could test positive later. Or you could be exposed later and then develop the illness. In other words, a negative test result does not mean you won’t get sick later. Know How to Protect Yourself and Others.

Serological assays for the presence of antibodies are used to identify individuals who were previously infected (including severe, mild, and asymptomatic cases) and have recovered (have been symptom free for 14+ days) and as such may now be potentially immune, which means that they are unlikely to transmit the virus to others. These tests are available thru your doctor’s office.

If you test positive for antibodies:

  • A positive test result shows that you have antibodies, which likely resulted from an infection with SARS-CoV-2, or possibly a related Coronavirus.
  • It is not clear if those antibodies can provide protection (immunity) against getting infected again. This means that we do not know at this time if antibodies make you immune to the virus, and/or protect you from reinfection or how long the immunity may last.
  • If you have no symptoms, you likely do not have an active infection and no additional follow-up is needed.
  • It’s possible you might test positive for antibodies and you might not have or ever had symptoms of COVID-19. This is known as having an asymptomatic infection, or an infection without symptoms.

If you test negative for antibodies:

  • You probably did not have a previous infection of COVID-19. However, you could have a current infection. It is possible you could still get sick, if you have been exposed to the virus recently, since antibodies don’t show up for 1 to 3 weeks after infection.
  • Some people may take even longer to develop antibodies, and some people may not develop antibodies at all even if they had the illness.
  • If you have symptoms and meet other guidelines for testing, you would need the Diagnostic test described above, not the Antibody test.

A serologic test alone cannot tell you definitely if you’ve had COVID-19.

Several dozen companies, many from China, sell at least 140 different diagnostic and antibody tests online in the U.S., without seeking FDA approval.  The quality of these tests is questionable. European countries discarded and returned more than 1,500,000 tests imported from a Chinese company, after finding they were far less accurate than advertised.

For more information on testing and other COVID-19 related issues, including prevention, treatment and immuno-boosting supplements, please schedule an appointment with Dr. Val Koganski at 215-750-7000 or https://www.NewtownInternalMedicine.com