Testing for Infections
Who should be tested for COVID-19?
Individuals who have symptoms of COVID-19 should consider being tested, depending on local health regulations.
In addition, you may need to be tested, even if you do not have symptoms, if you:
- have been in close contact with someone who has tested positive for the virus;
- work in a healthcare facility or as first responders;
- live or work in long-term care facilities, such as nursing homes, or other places where people live in close proximity to each other, such as homeless shelters;
- need a medical procedure or are being cared for in a hospital or long-term care facility; or
- need to be cleared for travel or work.
What type of test is used to detect a current COVID-19 infection?
Two tests can identify whether you currently have COVID-19:
- RT-PCR (seen as the Gold Standard): this is the most accurate test, but may take 24-72 hours, or in some cases even longer, to get results because samples need to be analyzed at an appropriately-equipped laboratory.
- Antigen tests: these tests tend to be faster, with results returned as quickly as 30 minutes, but they are less accurate than the RT-PCR test. This means that the test may not detect all infections so there is a chance that some individuals carrying the COVID-19 virus may get a negative result (called a false-negative test). Similarly, there is also a chance that an individual infected with a virus other than COVID-19, like the virus that causes the common cold, may test positive for COVID-19 (called a false-positive test).
If you have the option, choose the RT-PCR test as this offers more accurate results.
In some countries, an antibody test may also be available. This test tells you whether you had COVID-19 at some point in the past so they should NOT be used to assess if you have an active infection. An antibody test shows you if you have a specific protein in your blood that is produced when your body fights a virus like COVID-19 from a past infection. There is a chance, however, that a positive result means that you have antibodies for a virus from the same family of viruses as COVID-19, like the one that causes the common cold.
While antibodies typically protect you from getting the same infection again, there still is not sufficient data to understand if and how much protection COVID-19 antibodies might provide. Testing for antibodies also does not confirm whether you will spread COVID-19 so it is important that you continue to take precautions by staying at home, maintaining physical distance from others, wearing a face covering and isolating yourself if you experience symptoms.
How is the test administered? Is it painful?
For RT-PCR and antigen tests, a doctor, nurse or lab technician inserts a thin, flexible stick with cotton at the tip into your nose to collect an adequate sample of your mucous. The swab is kept in place for several seconds before it is gently rotated as it is pulled out, and is sealed in a tube to be sent to a lab for analysis. Swabs may be required from both nostrils to collect enough mucous for the test. This can be somewhat uncomfortable but is not overly painful.
For antibody tests, a blood sample is required.
How long does it take to get the test results?
The time to get your results depends on the type of test used. Some testing centres and clinics offer antigen tests, which means you can get your results within an hour or on the same day that you are tested. Other centres use a RT-PCR test where samples may have to be sent to an external lab for analysis. If this is the case, your results may not be available for a few days. Regardless of the test used, you should self-isolate or quarantine while you wait for the results.
What should I do if I test positive?
A positive test result means that you most likely have COVID-19 now and should self-isolate: stay home, separate yourself from others, and take precautions to reduce the risk of spreading the virus, including using a face covering and practicing good hand hygiene and physical distancing. If your symptoms get worse, you should contact your local health care provider by phone.
Once all of your symptoms have resolved and you have completed your isolation period as directed by your health care provider, you do not need to be tested again.
If you live in a household with other family members, it is important that your family also take precautions to reduce their risk of being infected and further spreading the virus. All family members who experience symptoms of COVID-19 should also be tested and should self-isolate until their symptoms have resolved.
What should I do if I test negative?
A negative test result means that you most likely do not have COVID-19. You should continue to practice good hand hygiene, physical distancing and wear a face covering. This is especially important if you have symptoms because it is possible you have the virus but the test did not detect it. If you believe you have tested negative and may, in fact, be infected, speak to your health care provider about being tested again.
Can someone test negative and later test positive for COVID-19?
Yes, either because the test did not detect the virus or because you were infected after you took the test.
Can someone test positive by error?
It is rare for someone to get a false-positive result from the RT-PCR and antigen COVID-19 diagnostic tests. If you have tested positive, it is critical that you self-isolate so to ensure you do not spread the virus to others.
Where should you go to get tested for COVID-19?
Most countries have COVID-19 testing centres to make it easy for people to be diagnosed. To learn more about testing facilities in your area, please contact your local Aga Khan (Jamati) Health Board or government health agency for details.
Is there currently a test shortage in the world?
Given how widely the COVID-19 pandemic has spread across the world, RT-PCR tests have been in short supply. For this reason, local authorities may prioritise those who have access to tests.
How much does a COVID-19 test cost?
The cost varies from country to country. Your doctor or local clinic can provide you with more accurate information about the cost of COVID-19 tests in your area.
Is the test for children the same as the one for adults?
There is no difference between the COVID-19 diagnostic test used for adults and children.
Are there any side effects from being tested?
There is no evidence to suggest the COVID-19 diagnostic test causes any side effects.