A method of assessing a patient for evidence of clubbing of the fingers. The patient is asked to place the nails of the right and left index fingers against each other. In health, a small diamond-shaped gap is seen between the proximal margin of the nails. In patients with clubbing, this gap is filled by tissue. Clubbing of the digits is found in some patients with serious lung diseases, such as lung cancers and chronic obstructive lung disease.