ICD-10 · PDGM grouping
G13 Systemic atrophies primarily affecting central nervous system in diseases classified elsewhere
All 4 codes in the G13 family, with the PDGM clinical group, comorbidity subgroup and primary-position rule CMS assigns, read from the CMS grouper crosswalk v07.2.26 and the CDC FY2027 code file.
Codes in family
4
Can lead a claim
0
Cannot lead a claim
4
What CMS assigns to G13
None of the 4 codes is assigned a clinical group. Comorbidity subgroups: 2 toward Alzheimer’s disease and related dementias; 1 toward Nondiabetic neuropathy; 1 is assigned none. None can lead a claim. CMS attaches a code-first note to all 4.
- Alzheimer’s disease and related dementias: counts toward the high comorbidity tier only in an interaction pair.
- Nondiabetic neuropathy: counts toward the high comorbidity tier only in an interaction pair.
Code first
CMS grouper convention 9, on G13.0, G13.1. Code first:
- neoplasm (C00-D49)
CMS grouper convention 12, on G13.8. Code first:
- underlying disease
CMS grouper convention 33, on G13.2. Code first:
- hypothyroidism (E03.-)
- myxedematous congenital iodine deficiency (E00.1)
- underlying disease, such as:
Every code in G13
Descriptions are CDC’s FY2027 wording; where CMS’s grouper abbreviates one, its form is shown beneath.
| Code | Description | Primary position | Clinical group | Comorbidity subgroup |
|---|---|---|---|---|
| G13.0 | Paraneoplastic neuromyopathy and neuropathy | Cannot lead a claimManifestation code is not reportable as principal diagnosis | None | Nondiabetic neuropathy |
| G13.1 | Other systemic atrophy primarily affecting central nervous system in neoplastic diseaseCMS: Oth systemic atrophy aff cnsl in neoplastic disease | Cannot lead a claimManifestation code is not reportable as principal diagnosis | None | None |
| G13.2 | Systemic atrophy primarily affecting the central nervous system in myxedemaCMS: Systemic atrophy primarily affecting the cnsl in myxedema | Cannot lead a claimManifestation code is not reportable as principal diagnosis | None | Alzheimer’s disease and related dementias |
| G13.8 | Systemic atrophy primarily affecting central nervous system in other diseases classified elsewhereCMS: Systemic atrophy aff cnsl in oth diseases classd elswhr | Cannot lead a claimManifestation code is not reportable as principal diagnosis | None | Alzheimer’s disease and related dementias |
Sources: CMS HH PPS Grouper Software v07.2.26, effective 2026-10-01, for the clinical group, comorbidity subgroup, code-first conventions and primary-position flags; CDC NCHS ICD-10-CM FY2027 code descriptions for the family title and code wording. This is the crosswalk Medicare runs a claim through. Grouping also depends on admission source, timing, the OASIS functional items and the rest of the diagnosis list.
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