Emma Norton, oncology nurse advisor at Bupa UK, is calling on people to place the nails of their index fingers together, as if making the top of a heart.
Most see a diamond-shaped gap between the nails. If this is missing, it could be a sign of “finger clubbing”, she warns.
This seemingly unusual symptom occurs in up to 35% of lung-cancer patients, according to Cancer Research UK.
“Most people with lung cancer don’t know their fingers are clubbing unless they know specifically to look out for it”, Ms Norton told HuffPost.