G47.421 — Narcolepsy in conditions classified elsewhere with cataplexy
Is G47.421 billable?
Yes — G47.421 is billable for FY2027. G47.421 is a valid, billable ICD-10-CM code at the highest level of specificity in its branch. G47.421 may be submitted for encounters from October 1, 2026 through September 30, 2027.
G47.421 at a glance
| Code | G47.421 |
|---|---|
| Description | Narcolepsy in conditions classified elsewhere with cataplexy |
| Billable | Yes |
| Code set | ICD-10-CM FY2027 |
| Valid for encounters | October 1, 2026 – September 30, 2027 |
What Medicare edits apply to G47.421?
The Medicare Code Editor screens inpatient claims before they are grouped. These edits name G47.421 directly.
This code describes a manifestation of an underlying disease. The underlying condition must be sequenced before it, so it can never be the principal or first-listed diagnosis.
Which MS-DRGs does G47.421 group to?
G47.421 sits in MDC 01 and helps define the logic of 3 MS-DRGs (version 44, FY2027). Which one a stay actually groups to also depends on procedures and secondary diagnoses.
- 091Other Disorders of Nervous System with MCCmedical
- 092Other Disorders of Nervous System with CCmedical
- 093Other Disorders of Nervous System without CC/MCCmedical
How is G47.421 listed in the Alphabetic Index?
These are the routes through the Alphabetic Index that lead to G47.421. They show the wording a clinician may have documented, which often differs from the Tabular description.
- Narcolepsy › in conditions classified elsewhere › with cataplexy
Code first — inherited from G47.42
The underlying condition below must be sequenced before G47.421. G47.421 describes a manifestation and cannot be the principal or first-listed diagnosis.
- underlying condition
Excludes2 — not included here — inherited from Chapter 6
The conditions below are not part of G47.421, but a patient may have both at the same time. When documentation supports it, G47.421 and the excluded code may both be reported.
- certain conditions originating in the perinatal period (P04-P96)
- certain infectious and parasitic diseases (A00-B99)
- complications of pregnancy, childbirth and the puerperium (O00-O9A)
- congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)
- endocrine, nutritional and metabolic diseases (E00-E88)
- injury, poisoning and certain other consequences of external causes (S00-T88)
- neoplasms (C00-D49)
- symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)
Excludes2 — not included here — inherited from G47
The conditions below are not part of G47.421, but a patient may have both at the same time. When documentation supports it, G47.421 and the excluded code may both be reported.
How long has G47.421 existed?
G47.421 has been in ICD-10-CM since at least FY2016, the earliest fiscal year on record here.
Derived from the official order files for FY2016–FY2026. FY2017 and FY2020 publish no order file, so those years are not covered.