PCR, Antigen, Antibody TESTS FOR COVID-19
COVID-19 Testing Overview
Types of tests
Tests for COVID-19 are available to check for a current or previous infection. A virus test will show if you have a current infection. Two types of viral tests can be used: nucleic acid amplification tests (NAAT) and antigen test (rapid test) or an antibody test (also known as a serologic test sample) can tell you if you have had an infection in the past. Antibody tests should not be used to diagnose an ongoing infection.
PCR or molecular test is used to directly screen for viral RNA, which will be found in the body before antibodies form or symptoms of disease appear. This means tests can determine if someone has the virus at an early stage of the disease. During PCR testing for Covid-19, substances known as reverse transcriptase or DNA polymerase are added to a nasopharyngeal sample in a laboratory. These substances create numerous copies of any viral RNA that may be present. This is to ensure that enough RNA copies are present to signal a positive result, as specially designed primers and probes attach to the virus’s genetic code sequences to signal the detection of a pathogen.
LFTs rapid test requirements are similar to PCR tests in that they are both types of antigen tests designed to detect active Covid-19 infection rather than disease antibodies. The main advantage of LFTs over PCRs is that they do not need to be submitted for confirmation, and instead provide results within 15-30 minutes. However, in what they get in speed, they sacrifice accuracy.
An antibody test shows how much of the population is infected. It won’t tell you who is infected because antibodies are generated after a week or two, after which the virus should have been removed from the system. But it tells you who was infected and who should be immune to the virus. A study published in the journal Immunity found that people recovering from even mild cases of Covid-19 produce antibodies for at least five to seven months, and can do so for much longer. Unlike PCR tests, which usually use swabs to detect Covid-19, blood samples are commonly used for antibody tests. This is because there will be very small amounts of Covid-19 circulating in the blood compared to the respiratory tract, but a significant and measurable presence of antibodies in the blood after infection.
Travel during a pandemic
International travelers should be aware of their international destinations before traveling due to the proliferation of new options and because the burden of COVID-19 varies globally.
Fully vaccinated travelers should undergo pre-departure testing if required at their destination. Fully vaccinated air travelers arriving from overseas must still have a negative SARS-CoV-2 virus test or COVID-19 recovery documentation before boarding a flight. International travelers are still advised to get tested for the SARS-CoV-2 virus 3-5 days after travel, regardless of vaccination status.
Who should get tested for a current infection (tests requirements)
- People who have symptoms of COVID-19.
- Most people who have had close contact (within 6 meter for a total of 15 minutes or more in 24 hours) with someone with confirmed COVID-19.
- Fully vaccinated people should be tested 3-5 days after known contact with someone with suspected or confirmed COVID-19 and wear a mask in public areas.
- People who have tested positive for COVID-19 in the past 3 months and who have recovered do not need to provide test certificate and negative test result or negative rapid test result after infection until they develop new symptoms.
The CDC recommends getting tested for anyone with any signs or symptoms of COVID-19, regardless of vaccination status or previous infection. If you are tested because you have symptoms or were potentially exposed to the virus, you should stay away from others awaiting test results and follow the advice of your healthcare provider or doctor.
How to get tested for current COVID-19 infection
Check with your healthcare doctor and the local health authority website for the latest testing information and test location. The type of COVID-19 testing method offered may vary by location You may also consider using a home collection kit or home test if you have signs and symptoms of COVID-19 and if you are unable to get tested with a healthcare provider or public health laboratories
How to use virus test results (PCR, Rapid, Antibody)
If the test is positive, find out what protective measures you need to take to prevent other people from getting sick. If your test is negative, you probably were not infected when the sample was collected in the laboratory. The test result only means that you did not have COVID-19 at the time of testing. Continue to take action to protect yourself.