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What is the difference between a PCR and an antibody test? We answer this and other common questions about coronavirus testing in our latest expert article…

What is the difference between a PCR and an antibody test?

There are two types of tests for COVID-19: a PCR laboratory test and an antibody immunoassay screening test. But what is the difference?

The polymerase chain reaction (PCR) test works by detecting specific genetic material within coronavirus (SARS-CoV-2). As such, it is used to confirm if an individual is currently infected with the virus. A long swab is used to collect a nasopharyngeal sample from the back of the nose and throat, which can be unpleasant. The sample is then sent off to a laboratory for testing.

Once the sample arrives at the laboratory, researchers extract its nucleic acid, which holds the virus’ RNA genome. They then amplify certain regions of the genome by using a technique known as reverse transcription PCR. This, in effect, gives researchers a large sample that they can then compare to SARS-CoV-2. However, the sample collection procedure must be performed correctly, or it can lead to false negatives. It has been recently reported that up to 30% of tests may have been affected in this way.

In contrast, antibody tests, also known as serological tests, look for specific antibodies in a blood sample that the body has produced to fight the virus. COVID-19 is new and therefore an individual will not have antibodies specific to it if they have not been infected.

An antibody test is advantageous because it can detect antibodies even if a patient has recovered, whereas a PCR test can detect the virus only if the person is currently infected. Another advantage is that the antibody test is significantly quicker. A PCR test has to be sent away to a laboratory for analysis, which can take around 2–3 days, whereas antibody tests can give results in minutes.

AlphaBiolabs’ antibody screening test

AlphaBiolabs’ IgM-IgG Combined Antibody Rapid Test, for professional and business use, can be bought online and sent to any business address.

The immunoassay testing device only requires a small amount of blood from a simple finger prick, to get results within 15 minutes. An instant result means an employer can make quick decisions about which workforce to isolate, and which to get back to work. 

The qualitative test works by detecting both early and late marker antibodies. This means that it can also provide information about the stage of infection. Immunoglobulin M (IgM) provides the first line of defence during viral infections, followed by the generation of immunoglobulin G (IgG). Detection of IgM antibodies tends to indicate a recent or current exposure to COVID-19. Whereas, detection of IgG antibodies indicates a later stage or previous COVID-19 infection, up to 6 weeks prior.

The coronavirus testing kits come with full instructions. AlphaBiolabs can also offer a sample collection option whereby a trained member of staff visits any premises to administer the testing or via an online portal. For further information or to order the coronavirus screening test, please visit our webpage. Alternatively, please contact our Customer Services team on 0333 600 1300, or email workplace@alphabiolabs.com