Modalities are the methods I use when I am investigating a client's issues. I am not a physician so I never diagnose my clients. But, I can use a variety of techniques that, when triangulated, can point to underlying issues that may be causing trouble for the client.
Techniques such as pH testing and muscle response testing can point to areas of the body that need support as well as which supplements will be most beneficial. It is important to give the body the support it needs so it is well-equipped to heal itself.