

This chapter includes symptoms, signs, abnormal results of clinical or other investigative procedures, and ill-defined conditions regarding which no diagnosis classifiable elsewhere is recorded.

They must be used in conjunction with an underlying condition code and they must be listed following the underlying condition. "In diseases classified elsewhere" codes are never permitted to be used as first listed or principle diagnosis codes. The code title indicates that it is a manifestation code. In most cases the manifestation codes will have in the code title, "in diseases classified elsewhere." Codes with this title are a component of the etiology/manifestation convention. These instructional notes indicate the proper sequencing order of the codes, etiology followed by manifestation. Wherever such a combination exists there is a "use additional code" note at the etiology code, and a "code first" note at the manifestation code. For such conditions, ICD-10-CM has a coding convention that requires the underlying condition be sequenced first followed by the manifestation. Certain conditions have both an underlying etiology and multiple body system manifestations due to the underlying etiology.
