ICD-10-CM Alphabetic Index · FY 2026 8,121 Terms
2026 ICD-10-CM Index to Diseases and Injuries ICD-10-CM
The Alphabetic Index is the front door of ICD-10-CM coding. It lists 8,121 main terms and 81,509 index entries, each pointing to a diagnosis code in the Tabular List. Look up the condition by its main term, walk the indented modifiers to the most specific line, then verify the code on its code page before you use it. The ICD-10-CM lookup tool searches the same index by keyword and synonym.
✓ Built from the official CMS FY 2026 index fileEffective Oct 1, 2025 – Sep 30, 2026
8,121
Main Terms
81,509
Index Entries
26
Letters
FY 2026
Dataset
Step 1
Find the main term
The condition, not the body part: Fracture, not Arm
Step 2
Walk the indents
Each level adds site, cause, or type detail
Step 3
Verify in the Tabular List
Open the code page and confirm notes and 7th characters
Browse the Index A to Z
A715 main terms
- Aarskog's syndrome
- Abandonment
- Abasia (-astasia) (hysterical)
- Abderhalden-Kaufmann-Lignac syndrome (cystinosis)
B401 main terms
- Baastrup's disease
- Babesiosis
- Babington's disease (familial hemorrhagic telangiectasia)
- Babinski's syndrome
C731 main terms
- Cachexia
- CADASIL (cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy)
- Café, au lait spots
- Caffeine-induced
D417 main terms
- Da Costa's syndrome
- Daae (-Finsen) disease (epidemic pleurodynia)
- Dabney's grip
- Dacryoadenitis, dacryadenitis
F270 main terms
- Faber's syndrome (achlorhydric anemia)
- Fabry (-Anderson) disease
- Facet syndrome
- Faciocephalalgia, autonomic
G269 main terms
- Gain in weight (abnormal) (excessive)
- Gaisböck's disease (polycythemia hypertonica)
- Gait abnormality
- Galactocele (breast)
H577 main terms
- H (Hartnup's) disease
- Haas' disease or osteochondrosis (juvenile) (head of humerus)
- H-ABC (hypomyelination with atrophy of the basal ganglia and cerebellum)
- Habit, habituation
I217 main terms
- I.Q.
- IBDU (colonic inflammatory bowel dissease unclassified)
- ICANS (immune effector cell-associated neurotoxicity syndrome)
- Ichthyoparasitism due to Vandellia cirrhosa
J32 main terms
- Jaccoud's syndrome
- Jackson's
- Jacquet's dermatitis (diaper dermatitis)
- Jadassohn-Pellizari's disease or anetoderma
M604 main terms
- Macacus ear
- Maceration, wet feet, tropical (syndrome)
- MacLeod's syndrome
- Macrocephalia, macrocephaly
N208 main terms
- Naegeli's
- Naegleriasis (with meningoencephalitis)
- Naffziger's syndrome
- Naga sore
P868 main terms
- Pachyderma, pachydermia
- Pachydermatocele (congenital)
- Pachydermoperiostosis
- Pachygyria
S701 main terms
- Saber, sabre shin or tibia (syphilitic)
- Sac lacrimal
- Saccharomyces infection
- Saccharopinuria
U118 main terms
- Uhl's anomaly or disease
- Ulcer, ulcerated, ulcerating, ulceration, ulcerative
- Ulcerosa scarlatina
- Ulcus
V148 main terms
- Vaccination (prophylactic)
- Vaccinia (generalized) (localized)
- Vacuum, in sinus (accessory) (nasal)
- Vagabond, vagabondage
W109 main terms
- Waiting list, person on
- Waldenström
- Waldenström-Kjellberg syndrome
- Walking
X18 main terms
- Xanthelasma (eyelid) (palpebrarum)
- Xanthelasmatosis (essential)
- Xanthinuria, hereditary
- Xanthoastrocytoma
Z13 main terms
- Zahorsky's syndrome (herpangina)
- Zellweger's syndrome
- Zenker's diverticulum (esophagus)
- Ziehen-Oppenheim disease
Reading the Index: Abbreviations and Conventions
NEC NEC "Not Elsewhere Classifiable"This abbreviation in the Alphabetic Index represents "other specified". When a specific code is not available for a condition, the Alphabetic Index directs the coder to the "other specified” code in the Tabular List.
NOS NOS "Not Otherwise Specified"This abbreviation is the equivalent of unspecified.
sevenChrNote 7th Character NoteCertain ICD-10-CM categories have applicable 7th characters. The applicable 7th character is required for all codes within the category, or as the notes in the Tabular List instruct. The 7th character must always be the 7th character in the data field. If a code that requires a 7th character is not 6 characters, a placeholder X must be used to fill in the empty characters.
excludes1 Type 1 ExcludesA type 1 excludes note is a pure excludes note. 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 Type 2 ExcludesA type 2 excludes note represents "Not included here". An excludes2 note indicates that the condition excluded is not part of the condition represented by the code, 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, when appropriate.
and "And"The word "and" should be interpreted to mean either "and" or "or" when it appears in a title.
with "With"The word "with" should be interpreted to mean "associated with" or "due to" when it appears in a code title, the Alphabetic Index, or an instructional note in the Tabular List.
The word "with" in the Alphabetic Index is sequenced immediately following the main term, not in alphabetical order.
see also "See Also"A "see also" instruction following a main term in the Alphabetic Index instructs that there is another main term that may also be referenced that may provide additional Alphabetic Index entries that may be useful. It is not necessary to follow the "see also" note when the original main term provides the necessary code.
see "See"The "see" instruction following a main term in the Alphabetic Index indicates that another term should be referenced. It is necessary to go to the main term referenced with the "see" note to locate the correct code.
codeAlso Code AlsoA "code also" note instructs that two codes may be required to fully describe a condition, but this note does not provide sequencing direction.
inclusionTerm Inclusion TermsThese terms are the conditions for which that code is to be used. The terms may be synonyms of the code title, or, in the case of "other specified" codes, the terms are a list of the various conditions assigned to that code. The inclusion terms are not necessarily exhaustive. Additional terms found only in the Alphabetic Index may also be assigned to a code.
includes IncludesThis note appears immediately under a three character code title to further define, or give examples of, the content of the category.
codeFirst Code FirstCertain 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.
sevenChrDef 7th CharacterIndicates that a seventh character is to be assigned to codes in a subcategory.
useAdditionalCode Use Additional CodeThe “use additional code” indicates that a secondary code could be used to further specify the patient’s condition. This note is not mandatory and is only used if enough information is available to assign an additional code.
Questions About the Index
What is the ICD-10-CM Index to Diseases and Injuries?
It is the alphabetical companion to the Tabular List. Every condition, symptom, and injury is filed under a main term with indented modifiers beneath it, and each line points to the ICD-10-CM code that fits that combination. CMS publishes it with every fiscal year release.
Why do some entries say "see" or "see also"?
A "see" note means the codes live under a different main term and you should look there. A "see also" note points to another main term that carries additional entries worth checking when the current entry does not match the documentation.
Can I code straight from the index?
No. The index gets you to a candidate code fast, but coding rules require verifying it in the Tabular List, where the instructional notes, exclusions, and 7th character requirements live. Every code on these pages links to its full code page for that check.
Related References
Source: Centers for Medicare & Medicaid Services, FY 2026 ICD-10-CM Index to Diseases and Injuries release files, effective October 1, 2025 through September 30, 2026.
