A coin test (or a bell metal resonance) is a medical diagnostic test used to test for a punctured lung.
A punctured lung can cause air or fluid to leak into the pleural cavity, leading to, for example, pneumothorax or hydrothorax.
A stethoscope is placed on the back to listen to breath sounds and the sound of the coins.
If a tinkling sound is heard, it is likely that air or fluid has found its way into the pleural cavity.
This medical diagnostic article is a stub.