20 C.F.R. § 220.113

Medical findings consist of symptoms, signs, and laboratory findings:

(a) Symptoms are the claimant's own description of his or her physical or mental impairment(s). The claimant's statements alone are not enough to establish that there is a physical or mental impairment(s).

(b) Signs are anatomical, physiological, or psychological abnormalities which can be observed, apart from the claimant's own statements (symptoms). Signs must be shown by medically acceptable clinical diagnostic techniques. Psychiatric signs are medically demonstrable phenomena which indicate specific abnormalities of behavior, affect, thought, memory, orientation and contact with reality. They must also be shown by observable facts that can be medically described and evaluated.

(c) Laboratory findings are anatomical, physiological, or psychological phenomena which can be shown by the use of medically acceptable laboratory diagnostic techniques. Some of these diagnostic techniques include chemical tests, electrophysiological studies (electrocardiogram, electroencephalogram, etc.) x-rays, and psychological tests.