How to use a rapid COVID-19 antigen test correctly

A rapid antigen test (ART) detects SARS-CoV-2 nucleocapsid proteins in a nasal specimen and returns a visual result in about 15 minutes. Accuracy depends heavily on collection technique, so it is worth taking a minute to do it properly.

Before you start: wash your hands, check the kit's expiry date, and let the sealed pouch reach room temperature. Lay out the swab, extraction buffer tube and test cassette on a clean, flat surface. Do not open the cassette until you are ready to test.

Collecting the sample: insert the swab about 2 cm into one nostril, angling it straight back rather than upward. Rotate it five times against the nasal wall, then repeat in the other nostril with the same swab. Mild discomfort is normal; bleeding is not — stop if it occurs.

Processing: place the swab into the buffer tube, stir for 10–15 seconds while pressing the swab head against the tube wall, then squeeze the tube as you withdraw the swab. Fit the dropper cap and dispense the exact number of drops stated in the instructions for use into the sample well.

Reading the result: read at the time stated on the insert, usually 15 minutes, and never after 30 minutes. A coloured control line (C) must appear for the test to be valid. Any visible test line (T), however faint, is a positive result. No control line means the test is invalid and must be repeated with a fresh kit.

After testing: seal all components in the disposal bag and wash your hands. If you are symptomatic and test negative, retest after 24–48 hours or seek a laboratory PCR test, as antigen sensitivity is lowest very early in infection.