Using rapid antigen tests to test for COVID-19

Using rapid antigen tests to test for COVID-19

Questions concerning the numerous rapid antigen tests and when to utilize them, as well as the strong demand for COVID-19 testing, persist. The director of Clinical Virology at Mayo Clinic, Matthew Binnicker, Ph.D., breaks down the various testing choices and explains how they operate.

Nasal swab polymerase chain reaction test

This test, which is carried out in a testing facility or a doctor’s office, searches for the RNA of the virus in a patient’s sample. An individual’s nostril is tapped with a nasopharyngeal swab to extract cells from the back of the nose for use as a sample. Patients may spit into a tube during several laboratory procedures to provide a sample of their saliva.

Nasal swab polymerase chain reaction test

If you have been exposed or are exhibiting symptoms, schedule a visit with your doctor.

You may anticipate receiving your findings within 24-72 hours, depending on the lab your physician employs. When it comes to COVID-19 testing, the polymerase test is considered the gold standard.

Nasal swab at home with a polymerase chain reaction test conducted at a lab

Similar rapid antigen tests are performed in the doctor’s office, however, in this instance, the patient gathers the nose swab themself and mails it to a lab for examination.

When symptoms first appear or soon after exposure, patients should take this test.

It usually takes three to seven days for at-home testing to provide results. Compared to at-home antigen testing, the findings of these polymerase chain reaction rapid antigen tests are more accurate since they are done in a lab.

Polymerase chain reaction test for saliva

Similar rapid antigen tests are conducted in the doctor’s office, but in this case, the patient gathers the saliva sample and mails it to a lab for analysis. Saliva is a specimen that may be obtained for polymerase chain reaction testing, much as swab rapid antigen tests. Comparatively speaking to a nasopharyngeal swab, collecting saliva from patients is often simpler and more pleasant.

Polymerase chain reaction test for saliva

After exposure or when symptoms start, patients should utilize this test.

It usually takes three to seven days to get results from at-home, mail-away testing. Compared to at-home antigen testing, the findings of these polymerase chain reaction rapid antigen tests are more accurate since they are done in a lab. You can also read about What is a COVID-19 Rapid Antigen Test by visiting

Rapid antigen tests at home

Certain viral proteins are discovered in the nasal sample by quick at-home antigen assays.

Patients should aim to do this test on the day of the event in order to get the greatest information on whether they have high levels of the virus in their system at that time. Timing is crucial with this test, so patients should strive to do so. Antigen testing using a nasal swab may provide findings in 15 minutes.

These rapid antigen tests are quicker and less costly than polymerase chain reaction testing, and they may be purchased anywhere at-home rapid antigen tests are marketed. However, there is a higher possibility of false-negative findings with these rapid antigen tests. Patients should continue to use a mask in public places and while near others who are unvaccinated or at high risk of contracting the illness, even if an at-home antigen test is negative.

Patients should have a lab-based polymerase chain reaction test the same day or the next day if the at-home test results in a positive result so that public health authorities may monitor the case and link the patient with a healthcare professional who can assess if treatment is required.

Analyses of antibodies

A serology or antibody test looks for antibodies in your blood that defend against the COVID-19 virus. After being sick or receiving a vaccination against an illness, your immune system produces proteins known as antibodies. For a while following, they may aid in preventing infection or serious sickness if you do get infected. The duration of this protection varies depending on the condition and the individual.

Rapid antigen tests shouldn’t be used to determine if someone is currently infected with the COVID-19 virus. Because it might take your body 1–3 weeks to produce antibodies following an infection, an antibody test may not be able to detect a present illness.

Analyses of antibodies

You could continue to test positive for a while after receiving a positive test result. After your first positive result, you can test positive for antigens for a few weeks. NAAT results might remain positive for up to 90 days. It might be challenging to determine if positive test results in a new infection since reinfections can happen within 90 days. If you have any queries or worries about your particular situation, think considering speaking with a healthcare professional.

How to interpret the outcome

If Your COVID-19 Test is


Any COVID-19 test that is positive indicates that the virus has been found and that you are infected.

  • To prevent others from contracting the infection, isolate yourself and take measures, such as wearing a premium mask.
  • Let others you’ve recently interacted with know they could have been exposed.
  • Keep an eye on your symptoms. Seek emergency attention right away if you experience any emergency warning symptoms.
  • You could think about getting in touch with a doctor, a community health center, or a pharmacy to find out what treatment alternatives might be available to you. To be successful, treatment must be started within a few days after the onset of symptoms.

o If you are an older adult or have a pre-existing medical condition, you are more likely to get very ill. You might perhaps be eligible for therapy.


A negative COVID-19 test indicates that the virus was not found, but it does not rule out the possibility that you may still be infected. FDA guidelines for repeat testing are available if you utilized an antigen test.

If you have symptoms,

  • You might have COVID-19 but were diagnosed with another sickness or you could have tested negative for the virus.
  • Practice normal measures for the public’s health to avoid infecting others.
  • If you have any concerns about your test results or if your symptoms become worse, get in touch with a medical professional.
  • If you were exposed to the virus that causes COVID-19 but do not yet have symptoms, you should keep taking the suggested precautions.
  • You may resume your usual activities if you don’t have any symptoms and haven’t been exposed to the COVID-19 virus.
  • Keep taking precautions to safeguard both you and other people, such as keeping an eye out for signs. If symptoms develop, get retested.
What is a COVID-19 Rapid Antigen Test

What is a COVID-19 Rapid Antigen Test

A result from the rapid antigen test (RAT), which checks for COVID-19 quickly, is available in 15 to 30 minutes. Every test kit has a QR code that connects to a video that demonstrates how to administer the test.

The right time to finish a Rapid Antigen Test

It is advised to utilize RATs if

  • going to a busy event with lots of people, such as a wedding or funeral
  • interacting with a person who is susceptible to COVID-19 hazards.
  • going to a high-risk location, such as a hospital, nursing home, or home for people with disabilities
  • You experience signs
  • You must immediately check for COVID-19.

Follow the Department of Health’s recommendation.

A Rapid Antigen Test location

What is a COVID-19 Rapid Antigen Test

For the benefit of the WA community, free Rapid Antigen Tests (RATs) are offered to help with the cost of living concerns and to encourage routine COVID-19 testing. For further details, go to the WA free RAT program website.

RAT kits may also be purchased from pharmacies, grocery stores, and other merchants.

Performing a Rapid Antigen Test

Two categories of RATs exist:

  • Saliva test, which involves spitting into a tube or sucking on a swab.
  • The user swabs each nostril with a nasal swab.

In self-test kits, you’ll find:

  • Test equipment
  • A nasal swab or spittle funnel
  • A test tube with a dropper top for sample collection
  • Deffer (a chemical solution that extracts the virus from samples)
  • Useful information

RATs for young people

All RAT kits include instructions on how to utilize them. Make sure the RAT is appropriate to use on kids and carefully follow the directions. RATs on children should be carried out or overseen by parents or guardians. Some individuals find it simpler to utilize “lollipop” saliva tests on small children.

A line adjacent to the C marker and no line next to the T marker indicates a bad outcome. You don’t need to isolate if your test is negative, you don’t exhibit any symptoms, and you don’t have any close contacts.

A line is placed next to the C and T marks to indicate a successful test. If you test positive, you must isolate for at least 5 full days and report your results online to WA Health. After five days, if you are still experiencing symptoms, keep to yourself until they go away.

RATs for young people

If there is just one line next to the T marker, your test results are invalid. This may occur if the test was conducted poorly or has a flaw. If this occurs, you must take a second test by registering for a free PCR test or retaking the RAT.

Adults and children are given step-by-step instructions by the emergency room nurse.


You have probably seen COVID-19 quick antigen test kits on sale at pharmacies, grocery shops, and online. Alternatively, it’s possible that the federal government, which is now sending one billion test kits to families throughout the country, is the source of your free kits. (You may place an order here.)

The quick antigen tests are practical and provide findings in 15 to 20 minutes. Self-testing, together with immunization, masking, handwashing, and social seclusion are crucial tools in the fight against coronavirus. It’s crucial to do the test correctly to get the most accurate results.

Claudio Alvarado, an assistant nurse manager in the pediatric emergency department at UC Davis Children’s Hospital, said, “We receive a lot of inquiries from families about how to administer the tests and how accurate they are. Although they are not difficult, it is crucial to carefully follow the instructions. Visit to read about The Ultimate Guide for ResMed AirFit N20.

RATs for young people

An instruction manual for doing a COVID-19 fast antigen test at home

  1. Spend at least 30 seconds thoroughly washing your hands with warm water and soap.
  2. Two tests are included in the set. A collecting swab, a test strip, and a tiny vial of liquid are the three primary components of each. Put each of them on a spotless surface.
  3. After opening it, place a collection swab into each nostril and rotate it five times against the inner wall. The swab should be inserted between 12 and 34 of an inch into the nostrils. Alvarado said, “A nice way to picture that is it’s roughly the size of the tip of your pinkie finger.” Then place the swab back into its packing; you’ll need it again. “Though it doesn’t hurt, it does feel extremely strange.”
  4. Tap the liquid vial’s bottom three times on a solid surface.
  5. Swab into the vial after opening the big top and stirring it 15 times.
  6. Pull the swab out while pressing the vial’s sides against it. This is an important step since it makes sure you have the whole collection, according to Alvarado. After that, replace the vial’s cap.
  7. Activate the test strip. Alvarado added, “You’ll notice that it has both a “C” and a “T.”
  8. Squeeze three drops of your sample into the strip’s collecting area by opening the smaller, top cap of the liquid vial.
  9. Set a 15-minute timer. During this period, refrain from touching the test strip.
  10. Read the exam.

How to interpret the outcomes of your at-home test kit

You’re going to check for two things after 15 minutes:

  • The control is a line beneath the letter “C.” If there isn’t a line under the “C,” you’ll need to retest, Alvarado said. “It’s crucial that you receive a line under the “C” because it signifies that the test is successful.
  • If there is absolutely no line in the region beneath the “T,” which stands for the test section, the result is COVID-19 negative. The test is positive for COVID if there is a line beneath the “T.” No matter how light or dark the line beneath the “T” is, Alvarado insisted that its presence indicates a positive COVID test.