G47.21 – Circadian rhythm sleep disorder, delayed sleep phase type
ICD-10-CM 2027 diagnosis code · Episodic and paroxysmal disorders
ICD-10-CM code
G47.21
- Code
G47.21(claims format:G4721)- Description
- Circadian rhythm sleep disorder, delayed sleep phase type
- Billable
- Yes – valid for HIPAA-covered transactions
- Valid for
- Dates of service October 1, 2026 – September 30, 2027 (FY2027)
- Chapter
- 6. Diseases of the nervous system (G00-G99)
- Block
- G40-G47 Episodic and paroxysmal disorders
- Parent codes
- G47 › G47.2
Notes for G47.21
Applicable to:
- Delayed sleep phase syndrome
Notes inherited from parent codes
Instructional notes at a category or block level apply to every code below it.
G47 – Sleep disorders
Excludes2 (not included here):
G47.2 – Circadian rhythm sleep disorders
Applicable to:
- Disorders of the sleep wake schedule
- Inversion of nyctohemeral rhythm
- Inversion of sleep rhythm
Index terms for G47.21
Entries in the ICD-10-CM alphabetic index that lead to this code:
Related codes in G47.2
- G47.20 – Circadian rhythm sleep disorder, unspecified typeBillable
- G47.22 – Circadian rhythm sleep disorder, advanced sleep phase typeBillable
- G47.23 – Circadian rhythm sleep disorder, irregular sleep wake typeBillable
- G47.24 – Circadian rhythm sleep disorder, free running typeBillable
- G47.25 – Circadian rhythm sleep disorder, jet lag typeBillable
- G47.26 – Circadian rhythm sleep disorder, shift work typeBillable
- G47.27 – Circadian rhythm sleep disorder in conditions classified elsewhereBillable
- G47.29 – Other circadian rhythm sleep disorderBillable
Frequently asked questions
What is ICD-10 code G47.21?
G47.21 is the ICD-10-CM code for circadian rhythm sleep disorder, delayed sleep phase type, in the block G40-G47 (Episodic and paroxysmal disorders).
Is G47.21 a billable code?
Yes. G47.21 is a billable/specific code that can be used to indicate a diagnosis for reimbursement purposes.
What category does G47.21 belong to?
It belongs to category G47 – Sleep disorders.
Source: CDC/NCHS ICD-10-CM FY2027 code files, tabular list and index. Reference only – code assignment must follow the official ICD-10-CM guidelines and documentation in the medical record.