By Sola Ogundipe

A simple, five-second finger test could be an early warning sign for lung cancer, experts say. Known as the “Schamroth window test,” it involves pressing your thumbnails together and looking for a diamond-shaped gap.

If this gap is missing, it could indicate finger clubbing, a potential symptom of lung cancer. While not a definitive diagnosis, this quick check can prompt individuals to seek medical attention if concerned.

The trick has been the subject of several viral social media posts and is often used as an early screening tool for the disease.

Finger clubbing happens when soft tissue at the ends of the fingers swell and make the nails change shape.

The exact mechanisms are unclear, though experts believe that it could be due to an overproduction of vascular endothelial growth factor (VEGF), a protein that tells blood vessels to grow.

This leads to increased blood flow to areas like the fingers, as well as fluid buildup throughout the body called edema and inflammation.

It’s believed that finger clubbing is more common with non-small lung cancer – the most common form – as 35 percent of patients report it.

It’s important to note that while finger clubbing can be a symptom of lung cancer, it’s not exclusive to the disease. In fact, only about 5% of lung cancer patients exhibit this symptom, and it can also be associated with other conditions like celiac disease, inflammatory bowel disease, and heart problems.

Ashley Vassallo, a lung cancer survivor diagnosed in her 30s, shared that finger clubbing was one of her earliest symptoms. Dr. Daniel Sugai, a dermatologist, has popularized the simple “Schamroth window test” on TikTok as a quick way to check for clubbing.

However, discovering a lack of a diamond-shaped gap between your nails doesn’t automatically mean you have cancer. It’s essential to consult a healthcare professional for a proper diagnosis if you have concerns.

The test has gained attention on social media as well. Dr Daniel Sugai, a dermatologist in Seattle, said on TikTok that he recommends the test and ‘especially’ worries about lung cancer in patients with finger clubbing.

Ashley Vassallo, who was diagnosed with stage four lung cancer in her 30s, said that finger clubbing was one of her first signs of the disease, though she didn’t learn about the diamond test until she was hospitalized.

In a TikTok video, Ashley showed a clip of fellow lung cancer survivor Aurora Lucas discussing the symptoms she had when she was diagnosed with lung cancer at age 28.

Aurora said that while she was being treated for cancer, her doctors would repeatedly check the shape of her fingernails, telling her the cancer could have caused it.