Know the Differences Between COVID 19 Tests and When to Get One

We hear daily about the number of people tested for COVID 19.  To date thousands of COVID 19 tests have been administered.  Most of these have been PCR tests that require a nasal and/or throat swab.  Recently another test has been made available that looks for COVID 19 antibodies and provides results much more quickly than the PCR test.

PCR covid 19 test
PCR tests use a cotton swab to obtain a sample from the nasal canal or throat.

PCR Tests Look for Active Infection

PCR tests look for the virus that causes COVID 19 by analyzing samples taken from a nasal or throat swab.  Results are sent to a lab for analysis which can take several days.  A positive PCR test means that the person tested has an active COVID 19 infection, even if they are not exhibiting any symptoms.  Those without symptoms could be contagious to others and not know it.

A negative PCR test indicates that the person was not infected when the sample was taken.  This does not mean that that person cannot contract the disease in the future.

Antibody Tests Can Tell Who Has Had COVID 19

covid antibody fingerstick test 1
Antibody tests require a small amount of blood obtained from a fingerstick.

Antibodies are formed in the body to fight off infections.  There are two types of antibodies created in those who either currently have the virus (IgM), or have had the virus (IgG).  To be tested a fingerstick blood sample is taken and analyzed.

A positive result for IgM shows antibodies that are currently fighting infection and that person has an active case of COVID 19. When IgG antibodies appear it means that the person being tested was infected with COVID 19 in the past.  In either case, those with positive results may not have exhibited any symptoms.

If an antibody test indicates someone has an active case of COVID 19 they should get a PCR test for confirmation. Quarantine protocols should always be followed after any positive current infection result. Mask and disinfection protocols should still be followed regardless of a negative test result.

Antibody tests are specifically for those that may be asymptomatic, but positive for COVID-19.  This can be very helpful if someone believes they have been exposed and may be around others who are elderly, have compromised health conditions, or young children.

COVID 19 test comparison chartWhich Test is Preferred?

The key advantage of the antibody test is results can be available in as little as 10 – 15 minutes.  This is much faster than PCR tests which often take several days to get test results back.  The antibody test also only requires a fingerstick to obtain a blood sample.  For most this method is preferred over the nasal swab.

If a person has an active infection with symptoms including fever, cough, sneezing, sore throat or extra tired, we DO NOT SUGGEST the antibody test. Those individuals should seek care at an urgent care or ER facility, or contact their primary care physician, to have PCR testing and follow up on their symptoms.

All Tests Have a Degree of Error

Both the PCR and antibody tests can give false negative results.  This means that the person tested has COVID 19, but the test did not indicate it.  The primary reason for this is that the test was administered at the time the person first became infected and the virus and/or antibodies were not yet present.  It may take 3 – 4 days for the virus to show on the PCR test; and 4 days to 3 weeks after exposure for the antibody test to show a positive result.

Kimi HathawayBlackbird Clinical Services Offers Antibody Testing

Antibody testing is available from Blackbird Clinical Services for those individuals wanting to know if they have or have had COVID 19, but have not exhibited any symptoms of the disease.

BCS will NOT take any patients that have a current fever or symptoms of COVID-19.  We will ask them to leave and direct them to their doctor or an urgent care facility.

There is PCR testing that is free to the public through a company called Optum.  Their toll free number is 888-634-1116.

For those wanting to learn more about the different COVID 19 tests that are available, please give us a call at 765-447-8700 or send us an email at KHathaway@blackbirdclinicalsvs.com.