A woman in the United Kingdom is raising awareness about an unusual method to check for lung cancer: a finger test.

This test involves looking for a condition called “finger clubbing,” which may indicate underlying health issues like lung cancer. Oncology nurse advisor Emma Norton says many people are unaware of this symptom and wouldn’t know to check for it.

The process of checking for clubbing is known as the Schamroth window test. It involves placing the fingernails of both index fingers together to see if a small diamond-shaped window is visible. If not, it may signal a health concern.