Which Covid-19 Tests are Considered Most Accurate?

image courtesy of Omar Medina

What happens when you test positive for Covid-19?

There are a few things to know before testing, and that is what type of tests are available and which are the most accurate?

To date there are three Covid-19 tests, the first being a rapid test known as an antigen test.

The antigen test or rapid test uses an oral, throat, or nose swab, that screens for Covid-19 proteins using a device such as BD Veritor System, commonly purchased on Amazon or other online shopping platforms.

BD Veritor Plus Analyzer courtesy of Amazon

The rapid test can display results within 15 to 30 minutes, yet as studies conclude, the rapid test may not be accurate, but can be a great tool for early discovery and implementing isolation precautions.

The Centers for Disease Control advised individuals who display Covid-19 symptoms, but test negative from a rapid antigen test, to follow up with a PCR test to confirm the results.

Due to improper collection technique, antigen tests can sometimes produce false positive results simply because they scan for additional viruses including type A & B influenzas.

Second type of Covid-19 test

The polymerase chain reaction.

The polymerase chain reaction (PCR) or RNA test, is a procedure in molecular biology used to amplify small amounts of DNA used as analysis for diagnosing the presence of disease.

Samples for PCR testing is primarily performed using mucus specimens from deep nasal or throat swabbing.

Typical result time is 1–3 days.

The PCR Test is considered the gold standard for diagnosing active coronavirus infection but does not indicate if you’ve had Covid-19 in the past.

Third Type of Coronavirus Test

The Covid-19 Antibody Test, also known as, Serology test, are screening tests for coronavirus antibodies using blood samples which determine if you were previously infected with the virus.

It is recommended that blood serum testing be done 14 days after exposure to Coronavirus.

Taking a blood serum test too soon, can cause inaccurate results.

Individuals develop antibodies when their body’s immune system responds to an infection.

In most coronavirus cases It usually takes a week for symptoms to appear after infection from SARS-CoV-2.

Antibodies will typically start presenting 2–3 weeks after infection from SARS-Cov-2.

So, let us use a hypothetical situation to better understand each testing procedure.

Situation #9

Brian works in a long-term-care facility where he receives a weekly test for Covid-19.

On December 18, 2020, Brian was tested by his employer using a rapid test, as well as a PCR test.

The rapid test conducted by his job revealed a positive result within 15 minutes, and Brian was placed on a 14-day quarantine by his employer as precautionary protocol.

The PCR sample was sent to an outside lab for additional screening.

Within two days, Brian’s result from the PCR Test was complete and revealed he was negative for Covid-19.

So, what happened here? Why did the two tests show conflicting results?

As stated before, rapid false positive or false negative results can occur due to mishandling specimen samples, and the rapid test’s ability to screen for other viruses including other respiratory tract infections not related to the SARS-COV-2.

In this scenario, Brian had the flu, and the rapid testing system picked up on the influenza virus, resulting in a positive test.

But the PCR test performed in the third-party laboratory was able to confirm that Brian did not have Covid-19.

For added confirmation, Brian requested a blood serum Covid-19 test 14 days later to determine if antibodies from the coronavirus had formed in his body.

With the use of the blood serum test, it was safe to say Brian had not been previously infected with the SARS-CoV-2 because no antibodies had formed within his body.

Brian was cleared to return to work.

As you can see, all three tests are vital to the screening and early detection of Covid-19 and must be used in conjunction to accurately diagnose the Covid-19 virus.

Current Covid-19 symptoms as stated by the CDC.

Fever or chills
Cough
Shortness of breath or difficulty breathing
Fatigue
Muscle or body aches
Headache
New loss of taste or smell
Sore throat
Congestion or runny nose
Nausea or vomiting
Diarrhea.

Please follow up with your health care provider for any of the reported symptoms.

And although the CDC has not confirmed, I believe the Covid-19 is an airborne disease, which would require employers, airline officials, Healthcare entities, and residential individuals to treat it as so.

New and improved rapid Covid-19 tests are now available to the public.

BinaxNOW is an antigen test that is available over the counter, which scans for antibodies after exposure to Sars-Cov-2. The test can be purchased at Walmart, CVS Pharmacy, and other retailers.

Wear a mask. Social distance. Follow the CDC guidelines.

REFERENCE:

BD 256066 Veritor Plus System Veritor Analyzer: Amazon.com: Industrial & Scientific

3 Types of COVID-19 Tests, and Which One Is the Most Accurate | Health.com

Symptoms of Coronavirus | CD

Polymerase Chain Reaction: Genetic Testing for COVID-19 Coronavirus (emedicinehealth.com)

Rapid Testing Is Less Accurate Than the Government Wants to Admit — ProPublica

FDA warns about potential false positive results with rapid COVID-19 antigen tests | Health Tips and News (timesnownews.com)

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