As the pressure of rising COVID positive cases has begun to test healthcare efficiency in India, we are reminded of how good health is extremely precious and staying home is the safest thing to do at the moment. Frontline workers who sadly do not have such an option are constantly working hard, putting their lives at risk every single day in order to provide essential services to the people of the nation. The heroes we need but do not deserve if we do not adhere to precautionary guidelines that have been laid out.
As months have passed, a lot more information has been unearthed from research on the virus. This has led us to understand the need for ramping up testing in the population. We now have three types of tests available to help fight the pandemic:
RT-PCR test
Type:Molecular diagnostic testThis test helps detect the genetic material (RNA) of the SARS-CoV-2 virus. It is considered to be the gold standard for COVID testing currently. Sample:Nasal or throat swabThe swab collects secretions present in the throat and nose. Viral particles can be detected in these secretions. The sampling is usually done by a trained physicianWhen it is done:When someone has been showing symptoms of COVID-19Symptomatic patients can reach out to a doctor online and receive a prescription sanctioning the test. The test basically detects the presence of the virus, the load of which is maximum when symptoms are exhibited. Interpretation of results: A positive result indicates that there is an active, ongoing COVID-19 infection. A negative result indicates that the virus has not been detected in the swab. If tested positive, you may be asked to isolate yourself at home or a COVID care centre, where your vitals need regular monitoring. Using a pulse oximeter to check for oxygen saturation and watching for breathlessness becomes important at this point.
If tested negative, you will still have to isolate yourself until symptoms subside. A re-test may be required if symptoms persist.
Advantages:A true positive test means that you most likely have the COVID-19 infection.
Less time for report output.
Disadvantages:A negative test does not necessarily mean that you do not have the infection due to the following reasons:
- Skilled and trained professionals are required to take the swab sample, else the test might not provide accurate results.
- During the initial phase of the infection, the viral load may be too low to be detected and hence re-test is necessary if symptoms persist.
Antigen tests
Type:Rapid diagnostic testThis test helps detect the antigens or specific proteins of the SARS-CoV-2 virus. It can be done in combination with an RT-PCR test. Sample:Nasal or throat swabThe swab collects secretions present in the throat and nose. Viral particles can be detected in these secretions. The sampling is usually done by a trained physicianWhen it is done:When someone has been showing symptoms of COVID-19Symptomatic patients can reach out to a doctor online and receive a prescription sanctioning the test. The test basically detects the antigens belonging to the virusInterpretation of results: A positive result indicates that there is an active, ongoing COVID-19 infection. A negative result indicates that the antigen has not been detected in the swab. If tested positive, you may be asked to isolate yourself at home or a COVID care centre, where your vitals need regular monitoring. Using a pulse oximeter to check for oxygen saturation and watching for breathlessness becomes important at this point.
If tested negative, you will still have to isolate yourself until symptoms subside. A re-test using RT-PCR method is usually done to confirm.
Advantages:A true positive test means that you most likely have the COVID-19 infection. It is a rapid diagnostic test.
Disadvantages:A negative test does not necessarily mean that you do not have the infection due to the following reasons:
- Skilled and trained professionals are required to take the swab sample, else the test might not provide accurate results.
- Although the test has high specificity, its low sensitivity does not make it dependable for negatively tested reports.
Serology tests
Type:Antibody tests: IgM and IgG (Non-diagnostic)This test helps detect the immune response of the body to the virus in the form of specific protein structures called antibodies. Sample:BloodA phlebotomist collects your blood sample. The titre of antibodies present in the blood gives an understanding of whether you have had COVID-19 infection in the recent past.When it is done:Asymptomatic individualsThe test does not require a prescription. People who are not exhibiting any kind of symptoms but want to know if they have had the COVID-19 infection in the recent past can take this blood test. The test, however, does not guarantee that you do not have an ongoing infection.What are IgM and IgG antibodies?IgM antibodies are produced by the body first in response to an active infection. They are slowly replaced by IgG antibodies, which provide immunity for a longer time.
It takes 2–6 weeks for the body to produce an immune response against the virus. The immunity provided by IgG is under research to ascertain if re-infections are possible.
Interpretation of results: Positive antibody results indicate that you may have had the COVID-19 infection in the recent past and your body has developed an immune response against the virus. If IgM and IgG are both positive, it indicates that you have had the infection recently and your body has developed these antibodies to fight it.
If both IgM and IgG are negative, it means that you have not had the infection recently. However, it does not determine if you have had immediate exposure to the virus or if you have an ongoing, active infection.
There are chances that you might get one antibody test positive and the other negative. Either way, it would be a good idea to follow the necessary precautions and re-test after a month.
Advantages:Collecting samples are easier and the process is less complex. A true positive test clearly signifies that you have had the infection in the recent past.
Disadvantages:The test is not for diagnosing an active COVID infection. If you develop symptoms or if you have recently been potentially exposed to the virus, this test will not help in predicting if you have or will get the infection.
Now that you know what these tests do, you will be able to choose what is best for you.
If you have any flu-like symptoms, please isolate yourself at home and speak to doctors online on MFine. If you have an ongoing illness, please make sure to have a pulse oximeter handy so you can stay aware of your oxygen levels.
