20 C.F.R. § 416.925
Listing of Impairments in appendix 1 of subpart P of part 404 of this chapter
(a) What is the purpose of the Listing of Impairments? The Listing of Impairments (the listings) is in appendix 1 of subpart P of part 404 of this chapter. For adults, it describes for each of the major body systems impairments that we consider to be severe enough to prevent an individual from doing any gainful activity, regardless of his or her age, education, or work experience. For children, it describes impairments that cause marked and severe functional limitations.
(b) How is appendix 1 organized? There are two parts in appendix 1:
(1) Part A contains criteria that apply to individuals age 18 and over. We may also use part A for individuals who are under age 18 if the disease processes have a similar effect on adults and children.
(2)(i) Part B contains criteria that apply only to individuals who are under age 18; we never use the listings in part B to evaluate individuals who are age 18 or older. In evaluating disability for a person under age 18, we use part B first. If the criteria in part B do not apply, we may use the criteria in part A when those criteria give appropriate consideration to the effects of the impairment(s) in children. To the extent possible, we number the provisions in part B to maintain a relationship with their counterparts in part A.
(ii) Although the severity criteria in part B of the listings are expressed in different ways for different impairments, “listing-level severity” generally means the level of severity described in § 416.926a(a); that is, “marked” limitations in two domains of functioning or an “extreme” limitation in one domain. (See § 416.926a(e) for the definitions of the terms marked and extreme as they apply to children.) Therefore, in general, a child's impairment(s) is of “listing-level severity” if it causes marked limitations in two domains of functioning or an extreme limitation in one. However, when we decide whether your impairment(s) meets the requirements of a listing, we will decide that your impairment is of “listing-level severity” even if it does not result in marked limitations in two domains of functioning, or an extreme limitation in one, if the listing that we apply does not require such limitations to establish that an impairment(s) is disabling.
(c) How do we use the listings? (1) Most body system sections in parts A and B of appendix 1 are in two parts: an introduction, followed by the specific listings.
(2) The introduction to each body system contains information relevant to the use of the listings in that body system; for example, examples of common impairments in the body system and definitions used in the listings for that body system. We may also include specific criteria for establishing a diagnosis, confirming the existence of an impairment, or establishing that your impairment(s) satisfies the criteria of a particular listing in the body system. Even if we do not include specific criteria for establishing a diagnosis or confirming the existence of your impairment, you must still show that you have a severe medically determinable impairment(s), as defined in §§ 416.921 and 416.924(c).
(3) In most cases, the specific listings follow the introduction in each body system, after the heading, Category of Impairments. Within each listing, we specify the objective medical and other findings needed to satisfy the criteria of that listing. We will find that your impairment(s) meets the requirements of a listing when it satisfies all of the criteria of that listing, including any relevant criteria in the introduction, and meets the duration requirement (see § 416.909).
(4) Most of the listed impairments are permanent or expected to result in death. For some listings, we state a specific period of time for which your impairment(s) will meet the listing. For all others, the evidence must show that your impairment(s) has lasted or can be expected to last for a continuous period of at least 12 months.
(5) If your impairment(s) does not meet the criteria of a listing, it can medically equal the criteria of a listing. We explain our rules for medical equivalence in § 416.926. We use the listings only to find that you are disabled or still disabled. If your impairment(s) does not meet or medically equal the criteria of a listing, we may find that you are disabled or still disabled at a later step in the sequential evaluation process.
(d) Can your impairment(s) meet a listing based only on a diagnosis? No. Your impairment(s) cannot meet the criteria of a listing based only on a diagnosis. To meet the requirements of a listing, you must have a medically determinable impairment(s) that satisfies all of the criteria of the listing.
(e) How do we consider your symptoms when we determine whether your impairment(s) meets a listing? Some listed impairments include symptoms, such as pain, as criteria. Section 416.929(d)(2) explains how we consider your symptoms when your symptoms are included as criteria in a listing.