Rapid antigen test kit: checking for COVID-19 antigens

A rapid antigen test kit looks for viral proteins in a sample to help identify a current COVID-19 infection.

The kit typically includes a swab, liquid buffer, a tube and a test device. After the sample is mixed with the buffer and applied to the device, marked lines are used to show whether the test detected the target antigen. Use only the result window and instructions supplied with your own kit, because products can differ.

Read the package instructions before starting and check the expiry date. Collect the sample from the site and in the manner specified by that kit. Follow its directions for mixing the sample, adding drops and reading the device. Reading too early or too late can make the result unreliable.

Wash or sanitise your hands before and after testing. Keep the kit parts on a clean, dry surface and do not reuse a swab or test device. If the control marking does not appear as described in the instructions, treat the test as invalid and use a new kit or arrange another test.

A negative result means the kit did not detect its target antigen in that sample at that time. It does not rule out COVID-19, especially if symptoms have just begun, the sample was difficult to collect, or exposure was recent. A positive result should be handled in line with current local public-health advice and any workplace, school or travel requirements.

The test does not assess how unwell someone is or explain every cause of fever, cough, sore throat or fatigue. COVID-19 can present with these symptoms, but symptoms alone do not establish the diagnosis.

A clinician may recommend a laboratory-based test or supervised testing when a result needs confirmation, symptoms and the result do not fit together, or a formal requirement applies. A COVID-19 Test service can advise on the appropriate test and collection method for your situation.

Keep note of your symptoms, the time of testing and whether you have had a known exposure. If you are unwell despite a negative result, seek clinical advice about repeat or alternative testing and about care for your symptoms. Follow the instructions provided by local health authorities for infection precautions after a positive result.

Do not share used swabs or test devices. Keep the buffer liquid away from eyes and mouth, and follow the kit instructions for disposal. Seek urgent medical help for severe breathing difficulty, persistent chest pain, new confusion, fainting, blue or grey lips or face, or difficulty staying awake; do not wait for a test result before getting help.