You will put a capsule in your mouth and take a large sip of water.
It will take up to 5 minutes for the capsule to dissolve, releasing the sponge in your stomach.
The nurse will pull up the sponge by the string. This will only take 1 or 2 seconds.
The sponge collect cells as it passes through your food pipe.
Experts will look at the sample to see if you have signs of Barrett’s oesophagus.