When one of the two targets, but not both, is present above the threshold for positivity, the test is reported as “inconclusive”. This is usually seen with low amounts of viral DNA. In practice, “inconclusive” results should be treated as presumptive positive COVID cases with a low viral load present.

What does it mean if a test for COVID-19 is equivocal?

An equivocal test result means that the result could not be interpreted as positive or negative.

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.

Can COVID-19 antigen tests be false positive?

Despite the high specificity of antigen tests, false positive results will occur, especially when used in communities where the prevalence of infection is low – a circumstance that is true for all in vitro diagnostic tests.

How long does it take for symptoms of COVID-19 to appear after exposure?

Symptoms may appear 2 to 14 days after exposure to the virus.

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Can an infected person spread COVID-19 before showing symptoms?

An infected person can spread COVID-19 starting 2 days before the person has any symptoms or tests positive. People who have COVID-19 don't always have obvious symptoms. A person is still considered a close contact even if they were wearing a mask while they were around someone with COVID-19.

What should you do if you have been around a person with COVID-19?

For Anyone Who Has Been Around a Person with COVID-19

Anyone who has had close contact with someone with COVID-19 should stay home for 14 days after their last exposure to that person.

Are COVID-19 molecular tests more accurate than antigen tests?

Molecular tests are generally more accurate and mostly processed in a laboratory, which takes longer; antigen tests—which are sometimes referred to as 'rapid tests'—are processed pretty much anywhere, including in doctor's office, pharmacies, or even at home.

What should be done if the COVID-19 antigen test result is positive?

In a community setting, when testing a person who has symptoms compatible with COVID-19, the healthcare provider generally can interpret a positive antigen test to indicate that the person is infected with SARS-CoV-2; this person should follow CDC's guidance for isolation. However, if the person who has received a positive antigen test result is fully vaccinated, the healthcare provider should inform the public health authorities. Ideally, a separate specimen would be collected and sent to a laboratory for viral sequencing for public health purposes.

What is a false positive COVID-19 antibody test?

Sometimes a person can test positive for SARS-CoV-2 antibodies when they do not actually have those specific antibodies. This is called a false positive.

Can the COVID-19 molecular test give false negatives?

Molecular tests are typically highly sensitive for the detection of the SARS-CoV-2 virus. However, all diagnostic tests may be subject to false negative results, and the risk of false negative results may increase when testing patients with genetic variants of SARS-CoV-2.

What does a negative COVID-19 antigen test result mean in asymptomatic persons?

Negative test results using a viral test (NAAT or antigen) in asymptomatic persons with recent known or suspected exposure suggest no current evidence of infection. These results represent a snapshot of the time around specimen collection and could change if tested again in one or more days.

Is the PCR test for COVID-19 accurate?

PCR tests remain the gold standard for detecting an active COVID-19 infection. The tests have accurately detected COVID-19 cases since the pandemic began. Highly trained clinical professionals are skilled at correctly interpreting PCR test results and notices like this one from the WHO.

Are there different types of COVID-19 diagnostic tests?

There are 2 different types of COVID-19 diagnostic tests -- molecular tests and antigen tests. Molecular tests detect the virus that causes COVID-19, SARS-CoV-2. Antigen tests detect specific proteins made by the virus.

How long can you spread COVID-19 after testing positive?

People with COVID-19 can spread the virus to other people for 10 days after they develop symptoms, or 10 days from the date of their positive test if they do not have symptoms. The person with COVID-19 and all members of the household should wear a well-fitted mask and consistently, inside the home.

What is meant by "presumptive positive cases" for the coronavirus disease?

A presumptive positive result is when a patient has tested positive by a public health laboratory, but results are pending confirmation at CDC. For public health purposes, a presumptive positive result using the CDC test is treated as a positive.

What to do if you test positive for COVID-19 on a home test?

If your COVID-19 test is positive, tell a healthcare provider about your positive result and stay in contact with them during your illness. To avoid spreading the virus to others, follow CDC's guidance for isolation.

How accurate are rapid COVID-19 antigen tests?

Rapid antigen tests are very specific for the coronavirus. A positive result likely means that you are infected. However, rapid antigen tests are not as sensitive as other tests, so there is a higher chance of a false negative result.

Does an antibody test diagnose an active COVID-19?

Antibodies can take several days or weeks to develop after you have an infection and may stay in your blood for several weeks after recovery. Because of this, antibody tests should not be used to diagnose an active coronavirus infection.

When are antigen tests the better option to screen for COVID-19?

The clinical performance of diagnostic tests largely depends on the circumstances in which they are used. Both antigen tests and NAATs perform best if the person is tested when their viral load is generally highest. Because antigen tests perform best in symptomatic people and within a certain number of days since symptom onset, antigen tests are used frequently on people who are symptomatic. Antigen tests also may be informative in diagnostic testing situations in which the person has a known exposure to a person with COVID-19.

Who should get a COVID-19 antigen test?

Those who are not fully vaccinated and have not had COVID-19 in the last 3 months should consider serial antigen testing if they have had contact with a person who has COVID-19 within the last 14 days. Serial antigen testing should be performed every 3–7 days for 14 days.

Which is more accurate nasopharyngeal or nasal swab for COVID-19 testing?

In other words, you are more likely to obtain a more accurate diagnosis when sampling with the nasopharyngeal (NP) swabs than you are with a nasal or throat swab.” For this reason, the nasopharyngeal swab has been the standard for reliable testing.

Should I be tested if I have been in close contact with someone who has COVID-19?

If you have been in close contact with someone who has COVID-19, you should be tested, even if you do not have symptoms of COVID-19. The health department may be able to provide resources for testing in your area.

Should I get tested after a close contact with someone who has COVID-19 if I am fully vaccinated?

• If you've had close contact with someone who has COVID-19, you should get tested 3-5 days after your exposure, even if you don't have symptoms. You should also wear a mask indoors in public for 14 days following exposure or until your test result is negative.

Who is considered a close contact of someone with COVID-19?

For COVID-19, a close contact is anyone who was within 6 feet of an infected person for a total of 15 minutes or more over a 24-hour period (for example, three individual 5-minute exposures for a total of 15 minutes). An infected person can spread COVID-19 starting from 2 days before they have any symptoms (or, if they are asymptomatic, 2 days before their specimen that tested positive was collected), until they meet the criteria for discontinuing home isolation.