Can at-home throat swabs help detect COVID-19?

A Mayo Clinic expert is urging people to use at-home COVID-19 tests only as directed. While online claims suggest that a throat swab may better detect the omicron variant of COVID-19 than a nasal swab, Dr. Matthew Binnicker, director of Clinical Virology at Mayo Clinic, says no scientific evidence supports that claim.

What tests are used to diagnose COVID-19?

Diagnostic tests can show if you currently are infected with SARS-CoV-2, the virus that causes COVID-19. There are two types of COVID-19 diagnostic tests:

Molecular tests, such as polymerase chain reaction (PCR) tests
Antigen tests, often referred to as rapid tests

What is the most accurate diagnostic test to detect COVID-19?

Reverse transcription polymerase chain reaction (RT-PCR)-based diagnostic tests (which detect viral nucleic acids) are considered the gold standard for detecting current SARS-CoV-2 infection.

What types of COVID-19 tests are available in the US?

Diagnostic tests can show if you have an active COVID-19 infection. Antibody or serology tests look for antibodies in a blood sample to determine if an individual has had a past infection with the virus that causes COVID-19 but cannot be used to diagnose current COVID-19 infection.

A demonstration of proper Nasopharyngeal swab technique for COVID-19 testing

What are the different types of viral tests?

Viral Test Types

• Laboratory tests can take days to complete and include RT-“PCR” tests and other types of nucleic acid amplification tests (NAATs).
• Rapid Point-of-Care tests can be performed in minutes and can include antigen tests, some NAATs, and other tests.

Which COVID-19 tests are more accurate PCR or antigen tests?

PCR tests are more accurate than antigen tests. "PCR tests are the gold standard for detecting SARS-CoV-2," says Dr. Broadhurst. "It is the most accurate testing modality that we have.

Are the COVID-19 PCR tests accurate?

PCR tests are very accurate when properly performed by a health care professional, but the rapid test can miss some cases.

Are molecular or rapid COVID-19 tests more accurate?

Molecular tests are generally more accurate and mostly processed in a laboratory, which takes longer; antigen tests—or “rapid tests”—are processed pretty much anywhere, including at home, in doctors' offices, or in pharmacies.

Why PCR is better than the rapid COVID-19 test?

“PCR tests are more reliable and accurate due to testing the specific genetic material of the virus, eliminating the interference from other viruses,” said Heather Seyko, a Laboratory Services manager for OSF HealthCare.

What is a PCR test in the context of COVID-19 testing?

A PCR test stands for polymerase chain reaction test. This is a diagnostic test that determines if you are infected by analyzing a sample to see if it contains genetic material from the virus.

What is the difference between a molecular test and rapid antigen tests for COVID-19?

Molecular tests are generally more accurate and mostly processed in a laboratory, which takes longer; antigen tests—or “rapid tests”—are processed pretty much anywhere, including at home, in doctors' offices, or in pharmacies.

Are CT scans helpful for diagnosing COVID-19?

Along with laboratory testing, chest CT scans may be helpful to diagnose COVID-19 in individuals with a high clinical suspicion of infection.

What is a self-home test for COVID-19?

Self-tests for COVID-19 give rapid results and can be taken anywhere, regardless of your vaccination status or whether or not you have symptoms. They detect current infection and are sometimes also called “home tests,” “at-home tests,” or “over-the-counter (OTC) tests.”

How accurate is the at-home QuickVue rapid COVID-19 test?

Quidel QuickVue rapid test Two lines mean a positive result. Accuracy: For people with symptoms, the QuickVue test correctly gave a positive result 83.5% of the time. It also correctly gave a negative result 99.2% of the time.

Can the omicron variant be detected by an at-home COVID-19 rapid test?

Several widely used rapid antigen at-home COVID-19 tests are effective at detecting omicron, according to preliminary research published Feb. 28 in MedRxiv.

When should you take a COVID-19 PCR test instead of a rapid antigen test?

“PCR would be chosen where there is a low likelihood of having the virus, but we want to be certain the patient doesn't have it. Antigen would be chosen if there is a high probability the patient has the virus (i.e. is experiencing symptoms), and we need to screen the patient as positive or negative,” Heather said.

What does a false-positive COVID-19 antigen test result mean?

A false-positive antigen test result means that the test says the person has COVID-19 but they are actually do not have COVID-19.

How long can you test positive for COVID-19 on a rapid antigen test?

Some people keep testing positive with rapid tests beyond five days, and some even test positive after 10 days, the newspaper reported.

Can a COVID-19 RT-PCR test be falsely negative?

RT-PCR tests are not perfect, Alland said. “After the first week of infection, there is a decline in virus shedding in the respiratory tract, where tests can become falsely negative,” he said.

How accurate are home COVID-19 tests?

Even though demand for COVID-19 tests greatly overwhelmed supply earlier in the pandemic, rapid home tests are more available today. While home tests provide a quick, accurate result, the flip side is that many test results are no longer reported to health authorities.

What are consequences of a false negative COVID-19 test?

Risks to a patient of a false negative test result include: delayed or lack of supportive treatment, lack of monitoring of infected individuals and their household or other close contacts for symptoms resulting in increased risk of spread of COVID-19 within the community, or other unintended adverse events.

What is the accuracy of the COVID-19 antigen test?

If possible, taking an at-home rapid COVID-19 test the day of the event is ideal. While these tests aren't 100% accurate, a negative result strongly suggests that you're not contagious at that particular time.

Can you get a false negative COVID-19 antigen test?

The antigen level in specimens collected either before symptom onset, or late in the course of infection, may be below the tests' limit of detection, resulting in a false negative antigen test result, while a more sensitive test, such as most NAATs, may return a positive result.

Do the U.S. COVID-19 rapid antigen tests use a nasal swab?

The rapid antigen tests that most people are using in the U.S. are specifically designed for nasal swabs.