Types of COVID-19 Tests, Explained

Michael Parry, MD, Director, Department of Infectious Diseases; Asha Shah, MD, Associate Director, Department of Infectious Diseases and Merima Sestovic, RN, Infection Preventionist

Here is what you need to know about testing being offered at Stamford Health:

• COVID-19 testing has come a long way since our first positive cases here at Stamford Health in early March.
• COVID-19 is an ever-evolving situation and we are constantly staying on top of the latest information, testing and treatments as they develop.
• Because of the rapid developments in testing, there has been some confusion around the different types of COVID-19 tests being offered.

What are the different types of COVID-19 tests and what do they all mean?

The "COVID-19 Test"

• What is it?
  Many of us in the medical world call this the PCR test (short for Polymerase Chain Reaction test).  PCR testing looks for RNA (the genetic material) of the virus. A positive result usually means you have the virus in your system, although the test sometimes shows a positive result for 2-3 weeks after the infection has disappeared.  
• How does it work?
  • We take a sample by inserting a swab into your nose and going straight back (nasopharyngeal swab) or by swabbing the back of your throat (oropharyngeal swab). 
  • We then test the fluid on the swab to detect the presence of the virus.
  • Because of recent advances, test results are available very quickly. 
• How can I get tested for COVID-19?
  • Please call your primary care physician if you are concerned about, or have symptoms of, COVID-19.  You need an order from your doctor to have this test at an outpatient testing location.
  • If you are admitted to Stamford Hospital with symptoms of COVID-19, or if you are being treated in the Emergency Department, we will test you for the virus. 
• When will I get my results?
  • If you are tested at an outpatient testing facility, you can expect test results in less than 24 hours. 
  • If you are tested as a patient admitted to Stamford Hospital or in our Emergency Department, your care team will quickly receive your results, sometimes in as few as 30 minutes.
• Can the COVID-19 test ever produce false negatives?
  On rare occasions, the tests can produce a false negative. This may be because the amount of the virus in your sample is so low, it can't even be detected or because not enough of your sample was taken for an accurate reading.

The COVID-19 Antibody Testing

• What is it?
  This test is not used to diagnose COVID-19. It is a blood test to determine if you have been exposed to COVID-19 at any point in the past – in which case your body would have created antibodies in response to the infection. Once created, antibodies typically help the body fight off an infection.  
• How do I get the antibody test?
  • If you are interested in the COVID-19 antibody test, you need an order from your doctor. You can get the test done at any of Stamford Health’s blood draw locations, but again, only with a doctor’s order.
  • If you do not have a doctor, Stamford Health Medical Group is open for both in-person and virtual visits and is accepting new patients. You can find a primary care physician (PCP) here.
• Is there any benefit to the COVID-19 antibody test?
  

  The CDC is still studying and determining the exact benefits to antibody testing. Here is what we know right now:

  • The test gives an estimate of how many people have been infected in order to determine how many in the public remain at risk.

  • This may help with trends and future predictions about the progression of the pandemic.

• Do I still need to wear a mask in public if I test positive?
  Yes. We do not yet know how much immunity you get from an infection with COVID-19, or how long that immunity will last. This is why you still need to wear a mask and exercise social distancing.
• When will I get my results?
  You can expect results within 24 hours.
• Can the COVID-19 antibody test ever produce false negatives?
  The antibody test Stamford Hospital uses is very accurate and sensitive. There is a small possibility that the test can produce a false negative if done too soon after the infection started in your body.

COVID-19 Plasma Infusion Study

• What is it?
  The COVID-19 plasma study is a relatively new clinical study that offers treatment to critically ill COVID-19 patients. This is not a diagnostic test or an antibody test.
• How does it work?
  

  Convalescent plasma (the liquid portion of blood without the red blood cells) is obtained by collecting blood from patients who have already recovered from COVID-19. The donor's plasma contains antibodies to help fight off the infection. It is hoped that the plasma will be helpful to very sick COVID-19 patients and speed their recovery. Donated plasma is drawn and processed by the New York Blood Center and the American Red Cross.

• Is this treatment working so far?
  This treatment is relatively new and we are studying its benefits every day. So far, initial results for Stamford Health patients appear to be promising.