ICD-10 Code for Autism Spectrum Disorder: F84.0
Codes verified against the CMS FY2027 ICD-10-CM code descriptions (effective October 1, 2026; these codes are unchanged from FY2026). Reviewed . See sources.
What is the ICD-10 code for autism?
The ICD-10-CM code for autism spectrum disorder is F84.0, Autistic disorder. "Autism spectrum disorder" is an inclusion term under F84.0 in the FY2027 tabular list, along with infantile autism and Kanner's syndrome. F84.0 is billable. F84 is a heading, and the rest of the family covers Rett's syndrome, Asperger's syndrome and unspecified pervasive developmental disorder.
Category F84, Pervasive developmental disorders, sits in the developmental section of Chapter 5 of ICD-10-CM. Autism spectrum disorder has a single code, F84.0, so the coding question is less about choosing among autism codes and more about the notes around it: the Excludes1 note for Asperger's syndrome, the "code also" instruction for associated medical conditions and intellectual disabilities, and the unspecified code F84.9.
This page lists each F84 code with its official FY2027 description, explains the instructional notes in the tabular list, and shows what a session note should contain so the diagnosis is supported. For the service side of ABA claims, see the ABA CPT codes.
F84 pervasive developmental disorder codes
| Code | Official description (FY2027) | Billable | When it fits |
|---|---|---|---|
| F84 | Pervasive developmental disorders | No (header) | Category only. Code also any associated medical condition and intellectual disabilities. |
| F84.0 | Autistic disorder | Yes | Inclusion terms: autism spectrum disorder, infantile autism, infantile psychosis, Kanner's syndrome. |
| F84.2 | Rett's syndrome | Yes | Documented Rett's syndrome. Excludes1 notes for Asperger's syndrome, autistic disorder and other childhood disintegrative disorder. |
| F84.3 | Other childhood disintegrative disorder | Yes | Documented childhood disintegrative disorder. Use additional code to identify any associated neurological condition. Excludes1 notes for Asperger's syndrome (F84.5), autistic disorder (F84.0) and Rett's syndrome (F84.2). |
| F84.5 | Asperger's syndrome | Yes | Inclusion terms: Asperger's disorder, autistic psychopathy, schizoid disorder of childhood. |
| F84.8 | Other pervasive developmental disorders | Yes | Other specified pervasive developmental disorders. |
| F84.9 | Pervasive developmental disorder, unspecified | Yes | Inclusion term: atypical autism. Use when a pervasive developmental disorder is documented without more detail. |
Is autism spectrum disorder coded F84.0?
Yes. The FY2027 Alphabetic Index lists "Autism" at F84.0, "Disorder, autism spectrum" at F84.0, and "Disorder, autistic" at F84.0. The tabular list confirms it: F84.0 is titled Autistic disorder, with the inclusion term "Autism spectrum disorder."
The Official Guidelines say code assignment is based on the provider's diagnostic statement that the condition exists, not on the clinical criteria the provider used to reach it (Section I.A.19). So the code follows the diagnosis the evaluating clinician has documented. A note writer does not need to restate diagnostic criteria to support F84.0; the diagnosis has to be in the record.
What does the "code also" note under F84 mean?
Category F84 carries a "code also" note: any associated medical condition and intellectual disabilities. The Official Guidelines explain that a "code also" note means two codes may be required to fully describe a condition, and that the note does not give sequencing direction (Section I.A.17). The sequence depends on the circumstances of the encounter.
Intellectual disabilities have their own section in Chapter 5, F70 to F79. For example, F70 is Mild intellectual disabilities and F79 is Unspecified intellectual disabilities. Whether an intellectual disability is present is the clinician's documented finding, so a note should record it only when the clinician has made that diagnosis.
Can F84.0 and Asperger's syndrome be coded together?
No. F84.0 has an Excludes1 note for Asperger's syndrome (F84.5), and Excludes1 means the two codes should never be used at the same time, except when the conditions are unrelated (Section I.A.12.a). F84.2, Rett's syndrome, has Excludes1 notes for Asperger's syndrome (F84.5), autistic disorder (F84.0) and other childhood disintegrative disorder (F84.3).
In practice this means one F84 code is chosen for the pervasive developmental disorder the clinician has documented. If the record describes a client who was diagnosed under an older label, the code still follows the diagnosis written in the current record.
When is F84.9 the right autism-related code?
F84.9, Pervasive developmental disorder, unspecified, has the inclusion term "atypical autism." It fits when the record documents a pervasive developmental disorder but does not specify which one. If the record states autism spectrum disorder, F84.0 is the more specific code, and the guidelines ask for the highest level of specificity the record supports (Section IV.F.3).
F84.8, Other pervasive developmental disorders, has the inclusion term "Overactive disorder associated with intellectual disabilities and stereotyped movements."
How does the autism code connect to ABA and therapy CPT codes?
The ICD-10-CM code says why the client is being seen; the CPT code says what service was provided. ABA services are reported with CPT codes such as 97153 for protocol-guided treatment and 97155 for treatment with protocol modification. Which diagnosis a payer requires for authorization, and which providers it accepts a diagnosis from, varies by payer. Confirm both with the payer before billing.
What should the session note show?
- The diagnosis in words as the evaluating clinician documented it (for example "autism spectrum disorder"), matching the code on the claim.
- Where the diagnosis comes from: the evaluating clinician and the date, so the record shows the diagnosis was made rather than assumed.
- Any associated medical condition or intellectual disability the clinician has diagnosed, since the F84 "code also" note points to them.
- Behavior and skill data in measurable terms: what the client did, how often, with what level of prompting.
- The intervention used in the session, the client's response, and the treatment plan goal it supports.
- Caregiver involvement and any home-practice instructions given, when part of the service.
- Use the ABA session note generator to draft the session note from what you recorded, then review and edit it.
Common mistakes
- Reporting F84 without a fourth character. F84 is a category heading, so the claim is invalid.
- Reporting F84.0 and F84.5 together despite the Excludes1 note.
- Leaving F84.9 on claims after the evaluating clinician has documented autism spectrum disorder.
- Adding an intellectual disability code that no clinician has diagnosed.
- Copying the diagnosis onto notes without the evaluator or date, so the record does not show where it came from.
- A diagnosis on the claim that never appears in the session note.
Frequently Asked Questions
What is the ICD-10 code for autism spectrum disorder?
F84.0, Autistic disorder. "Autism spectrum disorder" is one of its inclusion terms in the FY2027 tabular list, and the Alphabetic Index lists "Disorder, autism spectrum" at F84.0. It is billable.
What is the difference between F84.0 and F84.9?
F84.0 is autistic disorder, which includes autism spectrum disorder. F84.9 is pervasive developmental disorder, unspecified, with the inclusion term atypical autism. Use F84.9 only when the record does not specify which pervasive developmental disorder is diagnosed.
Is there a separate ICD-10 code for Asperger's syndrome?
Yes. F84.5 is Asperger's syndrome. F84.0 has an Excludes1 note for F84.5, so the two are not reported together.
Is F84 a billable code?
No. F84 is a category heading. The billable codes are F84.0, F84.2, F84.3, F84.5, F84.8 and F84.9.
Does the autism code change with severity?
No. The FY2027 F84.0 code has no severity characters. The code title and tabular list carry no severity level, so any level of support the clinician documents belongs in the note, not in the code.
Do I code an intellectual disability with F84.0?
Only if the clinician has documented one. Category F84 has a "code also" note for associated medical conditions and intellectual disabilities, and intellectual disabilities are coded in F70 to F79.
Did the autism code change for FY2027?
No. The FY2027 addenda list no additions, deletions or description changes for category F84. FY2027 took effect October 1, 2026.
Related references
Sources
- CMS: FY2027 ICD-10-CM code descriptions in tabular order (zip)
- CMS: FY2027 ICD-10-CM code tables, tabular and index (zip)
- CMS and NCHS: ICD-10-CM Official Guidelines for Coding and Reporting, FY2027 (PDF)
- CMS: ICD-10 code files (FY2027 and FY2026 ICD-10-CM)
- CDC NCHS: ICD-10-CM and the ICD-10-CM Browser Tool
Payer rules vary. Confirm diagnosis, coverage, modifier, and documentation rules with each payer before billing. This page is general education, not billing, coding, or legal advice. The diagnosis is the treating clinician's decision.
Draft the session note in SOAP, DAP, or BIRP
WellNotes drafts your session note from what you type or dictate. You choose the diagnosis and codes, and you review every note before it is used.