ICD-10-CM Official Coding Guidelines
FY 2026 — Official conventions, instructional notations, and chapter-specific coding rules. Download full PDF →
ℹInstructional Notations & Conventions
Includes:
The word 'Includes' appears immediately under certain categories to further define, or give examples of, the content of the category.
Excludes Notes
The ICD-10-CM has two types of excludes notes. Each note has a different definition for use but they are both similar in that they indicate that codes excluded from each other are independent of each other.
Excludes1
A type 1 Excludes note is a pure excludes. It means 'NOT CODED HERE!' An Excludes1 note indicates that the code excluded should never be used at the same time as the code above the Excludes1 note. An Excludes1 is used when two conditions cannot occur together, such as a congenital form versus an acquired form of the same condition.
Excludes2
A type 2 excludes note represents 'Not included here'. An excludes2 note indicates that the condition excluded is not part of the condition it is excluded from but a patient may have both conditions at the same time. When an Excludes2 note appears under a code it is acceptable to use both the code and the excluded code together.
Code First/Use Additional Code notes (etiology/manifestation paired codes)
Certain conditions have both an underlying etiology and multiple body system manifestations due to the underlying etiology. For such conditions the ICD-10-CM has a coding convention that requires the underlying condition be sequenced first followed by the 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. These instructional notes indicate the proper sequencing order of the codes, etiology followed by manifestation. 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. The code title indicates that it is a manifestation code. 'In diseases classified elsewhere' codes are never permitted to be used as first listed or principal diagnosis codes. They must be used in conjunction with an underlying condition code and they must be listed following the underlying condition.
Code Also
A code also note instructs that 2 codes may be required to fully describe a condition but the sequencing of the two codes is discretionary, depending on the severity of the conditions and the reason for the encounter.
7th characters and placeholder X
For codes less than 6 characters that require a 7th character a placeholder X should be assigned for all characters less than 6. The 7th character must always be the 7th character of a code
ChChapter-Level Notes
These notes apply to all codes within each chapter and define scope, inclusions, and coding rules.
- •diseases generally recognized as communicable or transmissible
- •certain localized infections - see body system-related chapters
- •carrier or suspected carrier of infectious disease (Z22.-)
- •infectious and parasitic diseases complicating pregnancy, childbirth and the puerperium (O98.-)
- •infectious and parasitic diseases specific to the perinatal period (P35-P39)
- •influenza and other acute respiratory infections (J00-J22)
- •code to identify resistance to antimicrobial drugs (Z16.-)
- •certain conditions originating in the perinatal period (P04-P96)
- •certain infectious and parasitic diseases (A00-B99)
- •complications of pregnancy, childbirth and the puerperium (O00-O9A)
- •congenital malformations, deformations and chromosomal abnormalities (Q00-Q99)
- •endocrine, nutritional and metabolic diseases (E00-E88)
- •injury, poisoning and certain other consequences of external causes (S00-T88)
- •neoplasms (C00-D49)
- •smoke inhalation (T59.81-)
- •symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)
- •code, where applicable, to identify:
- •exposure to environmental tobacco smoke (Z77.22)
- •exposure to tobacco smoke in the perinatal period (P96.81)
- •history of tobacco dependence (Z87.891)
- •occupational exposure to environmental tobacco smoke (Z57.31)
- •tobacco dependence (F17.-)
- •tobacco use (Z72.0)
- •certain conditions originating in the perinatal period (P04-P96)
- •certain infectious and parasitic diseases (A00-B99)
- •complications of pregnancy, childbirth and the puerperium (O00-O9A)
- •congenital malformations, deformations and chromosomal abnormalities (Q00-Q99)
- •endocrine, nutritional and metabolic diseases (E00-E88)
- •injury, poisoning and certain other consequences of external causes (S00-T88)
- •neoplasms (C00-D49)
- •symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)
- •certain conditions originating in the perinatal period (P04-P96)
- •certain infectious and parasitic diseases (A00-B99)
- •complications of pregnancy, childbirth and the puerperium (O00-O9A)
- •congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)
- •endocrine, nutritional and metabolic diseases (E00-E88)
- •lipomelanotic reticulosis (I89.8)
- •neoplasms (C00-D49)
- •symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)
- •systemic connective tissue disorders (M30-M36)
- •viral warts (B07.-)
- •arthropathic psoriasis (L40.5-)
- •certain conditions originating in the perinatal period (P04-P96)
- •certain infectious and parasitic diseases (A00-B99)
- •compartment syndrome (traumatic) (T79.A-)
- •complications of pregnancy, childbirth and the puerperium (O00-O9A)
- •congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)
- •endocrine, nutritional and metabolic diseases (E00-E88)
- •injury, poisoning and certain other consequences of external causes (S00-T88)
- •neoplasms (C00-D49)
- •symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)
- •certain conditions originating in the perinatal period (P04-P96)
- •certain infectious and parasitic diseases (A00-B99)
- •complications of pregnancy, childbirth and the puerperium (O00-O9A)
- •congenital malformations, deformations and chromosomal abnormalities (Q00-Q99)
- •endocrine, nutritional and metabolic diseases (E00-E88)
- •injury, poisoning and certain other consequences of external causes (S00-T88)
- •neoplasms (C00-D49)
- •symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)
- •supervision of normal pregnancy (Z34.-)
- •mental and behavioral disorders associated with the puerperium (F53.-)
- •obstetrical tetanus (A34)
- •postpartum necrosis of pituitary gland (E23.0)
- •puerperal osteomalacia (M83.0)
- •code, if applicable, from category Z3A, Weeks of gestation, to identify the specific week of the pregnancy, if known.
- •conditions that have their origin in the fetal or perinatal period (before birth through the first 28 days after birth) even if morbidity occurs later
- •congenital malformations, deformations and chromosomal abnormalities (Q00-Q99)
- •endocrine, nutritional and metabolic diseases (E00-E88)
- •injury, poisoning and certain other consequences of external causes (S00-T88)
- •neoplasms (C00-D49)
- •tetanus neonatorum (A33)
- •inborn errors of metabolism (E70-E88)
- •abnormal findings on antenatal screening of mother (O28.-)
- •certain conditions originating in the perinatal period (P04-P96)
- •signs and symptoms classified in the body system chapters
- •signs and symptoms of breast (N63, N64.5)
- •birth trauma (P10-P15)
- •obstetric trauma (O70-O71)
- •code to identify any retained foreign body, if applicable (Z18.-)
- •autoimmune disease (systemic) NOS (M35.9)
- •certain conditions originating in the perinatal period (P00-P96)
- •complications of pregnancy, childbirth and the puerperium (O00-O9A)
- •congenital malformations, deformations and chromosomal abnormalities (Q00-Q99)
- •endocrine, nutritional and metabolic diseases (E00-E88)
- •human immunodeficiency virus [HIV] disease (B20)
- •injury, poisoning and certain other consequences of external causes (S00-T88)
- •neoplasms (C00-D49)
- •symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)
- •transitory endocrine and metabolic disorders specific to newborn (P70-P74)
- •disorders of psychological development
- •symptoms, signs and abnormal clinical laboratory findings, not elsewhere classified (R00-R99)
- •certain conditions originating in the perinatal period (P04-P96)
- •certain infectious and parasitic diseases (A00-B99)
- •complications of pregnancy, childbirth and the puerperium (O00-O9A)
- •congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)
- •endocrine, nutritional and metabolic diseases (E00-E88)
- •injury, poisoning and certain other consequences of external causes (S00-T88)
- •neoplasms (C00-D49)
- •symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)
- •certain conditions originating in the perinatal period (P04-P96)
- •certain infectious and parasitic diseases (A00-B99)
- •complications of pregnancy, childbirth and the puerperium (O00-O9A)
- •congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)
- •diabetes mellitus related eye conditions (E09.3-, E10.3-, E11.3-, E13.3-)
- •endocrine, nutritional and metabolic diseases (E00-E88)
- •injury (trauma) of eye and orbit (S05.-)
- •injury, poisoning and certain other consequences of external causes (S00-T88)
- •neoplasms (C00-D49)
- •symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)
- •syphilis related eye disorders (A50.01, A50.3-, A51.43, A52.71)
- •certain conditions originating in the perinatal period (P04-P96)
- •certain infectious and parasitic diseases (A00-B99)
- •complications of pregnancy, childbirth and the puerperium (O00-O9A)
- •congenital malformations, deformations and chromosomal abnormalities (Q00-Q99)
- •endocrine, nutritional and metabolic diseases (E00-E88)
- •injury, poisoning and certain other consequences of external causes (S00-T88)
- •neoplasms (C00-D49)
- •symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)
- •certain conditions originating in the perinatal period (P04-P96)
- •certain infectious and parasitic diseases (A00-B99)
- •complications of pregnancy, childbirth and the puerperium (O00-O9A)
- •congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)
- •endocrine, nutritional and metabolic diseases (E00-E88)
- •injury, poisoning and certain other consequences of external causes (S00-T88)
- •neoplasms (C00-D49)
- •symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)
- •systemic connective tissue disorders (M30-M36)
- •transient cerebral ischemic attacks and related syndromes (G45.-)