As Omicron spreads throughout the United States, many people with and without symptoms employ quick and polymerase chain reaction (PCR) testing to identify if they have COVID-19(Covid-19 tests).
However, the Omicron variant’s rapid dissemination has complicated matters further, as testing supplies are limited, and several individuals report testing negative while having COVID-19.
Thus, when is a negative value genuinely negative, and when is it possible to be a false negative? When should we consult a physician to administer a test, and when will an at-home test suffice?
Tests of many types
COVID-19 tests are available in two flavors: diagnostic and antibody. The diagnostic tests are used to determine whether you have active COVID-19 disease, whereas the antibody tests determine whether you have ever had COVID-19.
Additionally, diagnostic tests are classified. These include molecular and antigen testing, more generally referred to as polymerase chain reaction (PCR), and fast tests.
These are also intended to identify an active SARS-CoV-2 infection, but they work differently. Again, the timing and severity of the condition are critical factors in determining how and when the tests should be employed.
To help you understand which test performs what and when you might need to take which, let’s examine what each does.
PCR Test
PCR testing is often conducted in a laboratory or healthcare setting. Using a swab, you or a technician will collect cells from your nose, mouth, or throat.
Following collection, materials are processed with an enzyme solution and analyzed under conditions of high amplification (copied multiple times). The technology enables testing laboratories to determine the precise genetic material included in a sample, including the identity of a particular virus. Additionally, the test can distinguish between distinct virus variants—or strains.
Because the tests evaluate minuscule fragments of a virus’s genetic content, they are highly reliable—often approaching 100%. The disadvantage of the technique is the length of time required and the requirement for laboratory analysis to obtain results.
While PCR tests can be run rapidly in an emergency, they typically take a few hours to complete. If you are not near the laboratory doing the test, this can add additional time. In addition, increased demand and the volume of tests performed by a single lab can potentially cause a delay in your results. When distance and demand are considered, the hours required to finish the test can become days.
The Food and Drug Administration (FDA) began approving at-home polymerase chain reaction (PCR) test kits in mid-2020. These kits enable you to collect a sample at home and then submit it to a lab for testing.
The Advantages and Disadvantages of PCR Tests
Pros
- Extremely precise
- Can identify viral infection in asymptomatic individuals
- It can be carried out at home
Cons
- Can be too sensitive (e.g., showing a positive result long after you are contagious)
- More costly
- Takes longer
- Results from home tests must be transmitted to a laboratory.
Rapid Examination
Instead of genetic material, rapid antigen testing looks for fragments of the SARS-CoV-2 virus’s viral proteins (antigens) that induce COVID-19 (nucleic acid from the virus). These rapid tests are frequently used to detect viruses that cause illnesses such as the flu, respiratory syncytial virus (RSV), and sexually transmitted infections (STIs).
The FDA has approved numerous quick antigen tests for COVID-19 due to their ease of use and accessibility. Additionally, they can produce findings in less than an hour.
The Advantages and Disadvantages of Rapid Antigen Tests
Pros
- It can be completed totally at home
- In less than an hour, you’ll have results.
- Costs less than a polymerase chain reaction (PCR) test
- Appropriate for repetitive or serial testing
- It’s beneficial to distinguish cold/flu symptoms from COVID-19 symptoms.
Cons
- Less precise than PCR
- Does not operate as well if no symptoms exist.
- Accuracy is contingent upon the quality of the sample collected.
- User error can affect the outcome.
Which Test Is Most Appropriate?
There is no correct or incorrect answer when determining which COVID-19 test is the best. Each variety has its own time and place, and the one you choose will depend on your situation and symptoms.
For instance, if you are ill and unsure whether COVID-19 causes your symptoms, a fast test can immediately provide an answer. That is advantageous since it would enable you to isolate yourself from other individuals, assisting in the virus’s transmission.
However, if you do not have symptoms or are only testing before an event to ensure you are not ill, a quick antigen test may not provide the best accurate result.
Individuals who are symptomatic and require testing before undergoing a medical procedure, individuals who require testing due to exposure to someone who has COVID-19, or individuals who continue to be ill despite repeated negative quick tests are the best candidates for PCR testing. While this testing method is more time-consuming and costly than fast tests, it can yield the most precise results.
Summary
Both PCR and fast antigen tests are reliable methods for testing if you suspect COVID-19-related symptoms. However, rapid antigen tests may be more effective if repeated (serial) testing is required.
Read More: Why You Should Do A Lab Test At Home
