All ICD10 Codes
F79Billable, valid for claims from October 1, 2026

Unspecified intellectual disabilities

In Intellectual Disabilities (F70-F79), chapter 5: Mental, Behavioral and Neurodevelopmental Disorders

  • F79 is an unspecified code: use it only when the record doesn't document anything more specific. If the record has more detail, check the other codes under F70-F79 below.
  • As a secondary diagnosis it is not a CC or MCC, so it doesn't raise the MS-DRG payment.
  • Doesn't count toward a Medicare Advantage risk score (no HCC in V28).
  • AHRQ's Chronic Condition Indicator classes it as chronic: expected to last 12 months or longer and to limit daily life or need ongoing care.
  • 65 US deaths in 2024 had an underlying cause in category F79, per the National Vital Statistics System on CDC WONDER. Death records use WHO ICD-10, so the count is for the whole category.

Also indexed as: Development, tardy, mental; Disability, intellectual

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Instructional notes

Includes: conditions that are coded here

  • Mental deficiency NOS
  • Mental subnormality NOS

Also applies, from Intellectual Disabilities (F70-F79)

These notes sit on F70-F79 and apply to every code under it, including F79.

Excludes1: not coded here, use a different code

  • borderline intellectual functioning, IQ above 70 to 84 (R41.83)

Code first: code the underlying condition first, then this code

  • any associated physical or developmental disorders

Official coding guidelines

From the ICD-10-CM Official Guidelines for Coding and Reporting, FY 2027 (CMS and NCHS). Links open the PDF at the right page.

Covers psychological pain disorders, substance use, abuse, dependence and remission, factitious disorder including Munchausen by proxy, and dementia severity.

Read Section I.C.5 (page 43)

Other codes under F70-F79

Intellectual Disabilities (F70-F79)

F79 MS-DRG

As the principal diagnosis, F79 groups to MS-DRG 884 (v44.0).

Related conditions

Grouped by AHRQ's Clinical Classifications Software Refined (CCSR), which sorts every diagnosis code into clinically meaningful categories.

F79 is in Neurodevelopmental disorders (MBD014, its default category), with 57 codes. Others in it:

  • F70 Mild intellectual disabilities
  • F71 Moderate intellectual disabilities
  • F72 Severe intellectual disabilities
  • F73 Profound intellectual disabilities
  • F78.A1 SYNGAP1-related intellectual disability
  • F78.A9 Other genetic related intellectual disability
  • F80.0 Phonological disorder
  • F80.1 Expressive language disorder

Medicare coverage articles listing F79

These 3 Medicare billing and coding articles list F79 as a diagnosis that supports medical necessity for the services they cover. From the CMS Medicare Coverage Database; check your own contractor's article before billing.

Other codes that refer to F79

Notes on these codes point to F79.

  • E00 Use Additional Code: code (F70-F79) to identify associated intellectual disabilities.
  • F80.0 Excludes2: speech articulation impairment due to intellectual disabilities (F70-F79)
  • F80.1 Excludes2: intellectual disabilities (F70-F79)
  • F80.2 Excludes2: intellectual disabilities (F70-F79)
  • F82 Excludes2: lack of coordination secondary to intellectual disabilities (F70-F79)
  • G93.45 Code Also: intellectual disabilities (F70-F79)
  • Q87.85 Code Also: intellectual disability (F70-F79)
  • Q87.87 Use Additional Code: intellectual disabilities (F70-F79)
  • Q87.88 Use Additional Code: intellectual disability (F70-F79)
  • Q90 Use Additional Code: code(s) to identify any associated degree of intellectual disabilities (F70-F79)
  • Q93.52 Use Additional Code: degree of intellectual disabilities (F70-F79)
  • QA0 Code Also: intellectual disabilities (F70-F79)
  • R41.83 Excludes1: intellectual disabilities (F70-F79)
  • Z15.1 Code Also: intellectual disabilities (F70-F79)
  • Z81.0 Includes: Conditions classifiable to F70-F79
  • Z91.83 Code First: intellectual disabilities (F70-F79)

About the condition

Plain-language background from MedlinePlus (National Library of Medicine), not coding guidance.

Developmental Disabilities

Developmental disabilities are conditions that are usually present at birth. They can affect a child's growth and development. These conditions can cause physical, learning, language, or behavior issues. They can include:

Read more about developmental disabilities on MedlinePlus

Code history

Valid since FY2016, when ICD-10-CM took effect on October 1, 2015. No changes since.

ICD-9-CM equivalent

Legacy crosswalk from the CMS General Equivalence Mappings (last updated 2018).

  • 319 Unspecified intellectual disabilities (approximate)
ICD-9 to ICD-10 converter