The Art of Classical Diagnosis
Classical Five Element Acupuncture places great importance on looking for , diagnosing and treating the actual cause of a persons distress.  This one Element, this one cause of imbalance in the person is known as the Causative Factor. 
Here is an introduction to each of these ancient diagnostic skills;

Colour   Sound   Odour   Emotion

The main and most trusted way of diagnosing this one Element is by the person's Colour, their Sound, Odour and Emotion.