What’s the difference between PCR, antigen & antibody testing for COVID-19?
Ever since 2020 happened, loads of COVID-19 tests have become available… but don’t they all test the same thing? Is there really a difference? Does it actually matter?
The various COVID-19 tests on the market are definitely NOT the same thing. It’s important to understand these differences to ensure the lab result is interpreted correctly. Especially if the results are yours or belong to someone you care about.
The main three tests on the market are (1) molecular tests, (2) antigen tests and (3) antibody tests. From now on we’ll refer to SARS-CoV-2, the virus that causes the disease called COVID-19.
Molecular vs. Antigen vs. Antibody
SARS-CoV-2 (COVID-19) Molecular Tests Explained
Of the 3 main types of testing, molecular is the most common.
These tests use a nasal, nasopharyngeal (the super deep and uncomfortable one) or saliva sample to look for the genetic blueprint of the SARS-CoV-2 virus. The blueprint is its RNA or ribonucleic acid.
These molecular, or nucleic acid tests are the gold standard. The greater medical community considers them the best because they can take a very tiny amount of RNA and amplify it with a process that makes tons of copies. These duplicates help identify if SARS-CoV-2 is present or not.
This amplification process is called Polymerase Chain Reaction (PCR). Don’t be fooled by the media – PCR technology is not new. It’s been used for many years to diagnose infectious diseases. Due to the complexity of the PCR method, these tests are usually sent off to a laboratory.
SARS-CoV-2 Antibody Tests Explained
Do you ever wonder if you were previously infected with COVID-19? With an antibody test, you can see if your immune system has responded to the SARS-CoV-2 virus in the past – regardless of if you experienced symptoms.
Your immune system produces different kinds of antibodies in response to any viral infection. In the case of SARS-CoV-2, IgG antibodies have been shown to last for up to 8 months, according to two studies from the NIH.
However, these antibodies do not stay in the body permanently, and another study found that while IgG antibodies lasted longer than IgA and IgM antibodies, they did decrease in the second and third month after infection, especially in those who had mild cases of COVID-19.
While testing for IgG antibodies can’t reveal if you’re currently infected with COVID-19 (it takes 1-3 weeks after getting infected for antibodies to develop), they can show if your body has built up possible immunity against COVID-19. If you’ve been vaccinated against COVID-19, you can even use an IgG antibody test to test how your vaccine measures up against its claims of effectiveness
What SARS-CoV-2 (COVID-19) test should I order?
Overall, the best way to get an accurate result is to order a molecular PCR test. Both positive and negative results are trustworthy.
Antigen and antibody testing certainly play an important role in fighting this pandemic. But do your homework before purchasing.
- First, cut through the marketing jargon. Be sure you can differentiate PCR, antigen and antibody testing.
- Second, read up on the clinician, company or laboratory selling you the product. Is the test FDA authorized? Is the lab CLIA certified? Does the brand have credibility?
- Third, compare turnaround time, eligibility and price. After your sample has shipped, does it take 2 days to get results or up to 7 days? Will they let you get SARS-CoV-2 testing even if you don’t have symptoms? Is the price comparable to similar tests on the market?
No matter what route you take, testing will always bring you one step closer to thriving. What one step are you planning to take?