U.S. ICD-10-CM reference · FY2027
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Free ICD-10-CM 2027 code lookup

Search diagnosis codes, explore the classification and read the official instructions. One clear reference for your next code lookup.

Current edition

October 1, 2026 – September 30, 2027

Edition details & official sources
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ICD-10-CM reference library

The indexes, tables and guidance you need, in one place.

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Tabular List

Explore diagnosis codes by chapter, category and subcategory.

Alphabetic Index

Find a diagnosis term and follow its code references.

External Causes Index

Look up the circumstances and causes of injuries.

Table of Drugs & Chemicals

Explore poisoning, adverse effect and underdosing references.

Table of Neoplasms

Browse neoplasm references by anatomical site and behavior.

Official Coding Guidelines

Read the conventions and guidance for the selected edition.

FY2027 ICD-10-CM code chapters

Follow a code range to its categories, complete codes and instructions.

22 chapters
01A00–B99Certain infectious and parasitic diseases02C00–D49Neoplasms03D50–D89Diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism04E00–E89Endocrine, nutritional and metabolic diseases05F01–F99Mental, Behavioral and Neurodevelopmental disorders06G00–G99Diseases of the nervous system07H00–H59Diseases of the eye and adnexa08H60–H95Diseases of the ear and mastoid process09I00–I99Diseases of the circulatory system10J00–J99Diseases of the respiratory system11K00–K95Diseases of the digestive system12L00–L99Diseases of the skin and subcutaneous tissue13M00–M99Diseases of the musculoskeletal system and connective tissue14N00–N99Diseases of the genitourinary system15O00–O9APregnancy, childbirth and the puerperium16P00–P96Certain conditions originating in the perinatal period17Q00–QA1Congenital malformations, deformations, chromosomal abnormalities, and genetic disorders18R00–R99Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified19S00–T88Injury, poisoning and certain other consequences of external causes20V00–Y99External causes of morbidity21Z00–Z99Factors influencing health status and contact with health services22U00–U49Codes for special purposes
Official U.S. code titles are shown in English.Open the complete Tabular List

Common diagnosis code lookups

Open an entry to read its full title, hierarchy and coding notes.

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I10Essential (primary) hypertensionE11.9Type 2 diabetes mellitus without complicationsM54.50Low back pain, unspecifiedF41.9Anxiety disorder, unspecifiedK21.9Gastro-esophageal reflux disease without esophagitisN39.0Urinary tract infection, site not specified

These are lookup examples. Code selection depends on the documented encounter and applicable instructions.

How to verify a diagnosis code

A search match is the beginning of a code review. Keep the official instructions close at every step.

Read the lookup walkthrough
  1. 01

    Start in the Alphabetic Index

    Find the documented condition and follow its modifiers and cross-references.

    Open the Alphabetic Index
  2. 02

    Confirm the Tabular entry

    Review the full code title, parent categories, exclusions and required characters.

    Browse the Tabular List
  3. 03

    Read the applicable guidelines

    Check the edition, setting-specific guidance and sequencing instructions.

    Read the official guidelines

ICD-10-CM coding guides

Practical explanations, worked examples and links back to the source.

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Edition and official sources

FY2027 · Effective October 1, 2026 – September 30, 2027. Code titles and instructions come from the published U.S. release files.

Common ICD-10-CM questions

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What is ICD-10-CM?

ICD-10-CM is the U.S. clinical modification of the International Classification of Diseases, Tenth Revision. It classifies diagnoses and reasons for healthcare encounters. This website covers U.S. ICD-10-CM diagnosis codes. Read the CDC/NCHS overview.

Which ICD-10-CM edition should I use?

Choose the edition whose effective dates apply to the encounter. FY2027 runs from October 1, 2026 through September 30, 2027. The April 2026 archive runs from April 1 through September 30, 2026. Confirm the applicable dates and setting-specific rules in the official release sources.

How do I find and verify a diagnosis code?

Start with the documented condition in the Alphabetic Index, then verify the suggested code in the Tabular List. Read the complete title, inclusion and exclusion notes, sequencing instructions and required characters before use.

Does a “billable” label guarantee reimbursement?

No. The label indicates a complete code in the source code-order data. It does not determine whether the code fits the medical record or meets a payer’s coverage rules. Learn what code status means.

Where do the code titles and instructions come from?

The reference uses published U.S. ICD-10-CM release files from CDC/NCHS and CMS. Official titles and instructions remain in English. The source library identifies the edition and the published materials.

Is ICD Code Hub a government website?

ICD Code Hub is an independent reference published by Pluginfinity LLC. It is not affiliated with CDC, NCHS or CMS. Educational guides are prepared with AI assistance and are not independently reviewed by a credentialed clinical coding specialist. Read our editorial policy.

An independent reference, with sources you can check. ICD Code Hub is published by Pluginfinity LLC. Use it for reference and education; verify code assignments against the official guidance and clinical documentation. About this website · Editorial policy & corrections