Testing for Covid-19 has become an important part of our lives today. Testing for the virus may be done if you have come into close contact with an individual diagnosed with Covid-19, if you have symptoms associated with Covid-19 or even to satisfy travel requirements for different countries in the world. There are different tests that are available today to test for the virus.
The first type is the Polymerase Chain Reaction (PCR) test. Samples taken would be taken to the lab for testing using this methodology. The sample is usually a nasopharyngeal swab. The test directly screens for the presence of viral RNA in the sample and can therefore diagnose whether the patient has the virus or not. The disadvantage for this type of testing is that the sample needs to be sent to a lab and can take days for the result to come back. The result has a 30% chance to be inaccurately negative.
The second type of test is the Lateral Flow Test. This is also a type of an antigen test similar to PCR tests. In this test, the sample is placed on a pad and drawn via a capillary line onto strips that are coated with antibodies specific to SARS-Cov proteins. If viral proteins are present, a colored line is formed indicating the virus is present. Results are usually ready within 30 minutes. The accuracy for these types of test is around 80%.
The third type of test is antibody tests. This test is not used to diagnose active infection but it does give an indication of past infection or those that have immunity against the virus. If there is a very large number of people who have immunity in a population, it will stop the virus from spreading, something known as ‘herd immunity’.