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

This test looks for a condition called “finger clubbing,” which can indicate serious health problems like lung cancer. Many people, says oncology nurse advisor Emma Norton, don’t know about this symptom or how to check for it.

The test, known as the Schamroth window test, is easy to perform. It involves placing the fingernails of both index fingers together. Normally, a small diamond-shaped gap—or “window”—appears between the nails. If this window is missing, it could be a sign of finger clubbing and may suggest an underlying health issue.

Finger clubbing happens when the tips of the fingers enlarge and the nails curve around the fingertips, often due to reduced oxygen levels in the blood. While it can be caused by various conditions, including heart and lung diseases, it’s an important warning sign that shouldn’t be ignored.

Raising public awareness about this simple test can help people spot potential lung cancer symptoms early and seek medical advice sooner. Early detection is critical for better treatment outcomes.

If you notice changes in your fingers or nails, especially the absence of the Schamroth window, it’s important to consult a healthcare professional for further evaluation.