What's the difference between COVID-19 antigen & antibody testing?
Learn more about testing & what it can tell us
We’ve put together a handy guide about the differences between antigen and antibody testing for COVID-19 (coronavirus). Read on to find out more.
What is an antigen test?
We know the main symptoms of COVID-19 include a high temperature, a new continuous cough and a loss or change in sense of taste and smell. Although you may not be showing symptoms of COVID-19, an antigen test can tell you if the virus is present in your body. It's a swab test from your nose and/or the back of your throat collected with a long cotton bud and analysed.
What an antigen test can tell you
This type of test can only tell you if you currently have an active COVID-19 infection. It can’t tell you if you’re immune to it or if you’ve had it before. If your antigen test is positive, you should self-isolate at home and follow government guidance. If you live with other people or are part of a support bubble, those you’ve had contact with should also self-isolate at home. If your test result is negative, you should continue to follow social distancing guidelines when leaving your home. Sometimes, results can be inconclusive, and this could be because the test was carried out incorrectly. If you’re symptomatic, it’s recommended you get a re-test and remain in self-isolation until you’ve got a negative test result.
If you don’t have coronavirus symptoms but would like a test if you’re travelling abroad or attending a social event (if tier guidelines allow), you can book a private COVID-19 swab test at selected Boots stores.*
What is an antibody test?
An antibody test is a blood test to check if you’ve had COVID-19 before. It works by checking for antibodies in your blood. It doesn’t test for an active COVID-19 infection. Your body makes antibodies when you get an infection and they help you to fight it off. The results from these tests can also help scientists learn more about the spread of the virus.
What an antibody test can tell you
Your antibody results won’t tell you how long you’re immune for so you should continue to follow social distancing and hand hygiene guidance – regardless of your antibody test result.
A positive test result means you have COVID-19 antibodies, so it’s likely you’ve had the virus before. The test won’t tell you when you had the infection. It also won’t tell you if you can/cannot spread the virus to other people. Currently, there’s no evidence to suggest that people who have had the virus develop long-lasting immunity that would prevent them from getting the virus again. You should continue to follow government guidance following your positive test result.
A negative test result means no COVID-19 antibodies were detected, so it’s unlikely you’ve been infected with COVID-19. It’s possible to have had the infection even if your antibody test result is negative. This can happen because some people don’t develop antibodies, or they don’t have enough antibodies for the test to detect.
An inconclusive test result means your test didn’t work. Whatever your test result, you must continue to follow the same guidelines as everyone else to protect yourself and others from the virus.
Information correct at time of publication (12.01am 15/01/2021)
*Our COVID-19 testing services are not suitable for anyone with symptoms of COVID-19, or anyone who thinks they may have COVID-19.