M35.1 Other overlap syndromes

Billable ICD-10-CM code, FY2026. Acts as a Complication or Comorbidity (CC) as a secondary diagnosis.

Applicable to

• Mixed connective tissue disease

Excludes1 (never code together)

• polyangiitis overlap syndrome (M30.8)

Applies from M35 Other systemic involvement of connective tissue

Excludes1 (never code together)

• reactive perforating collagenosis (L87.1)

Risk adjustment (HCC)

• CMS-HCC V22: HCC 40 — Rheumatoid Arthritis and Inflammatory Connective Tissue Disease
• RxHCC V08: HCC 84 — Systemic Lupus Erythematosus and Other Systemic Connective Tissue Disorders
• ESRD V24: HCC 40

MS-DRG index

Defines the logic of DRG(s) 545-547 in MDC 08.

Approximate ICD-9-CM (GEMs)

• 710.8 Other specified diffuse diseases of connective tissue (approximate)

Code annotations containing back-references to M35.1

Back-references to M35

• Type 2 Excludes: I77 Other disorders of arteries and arterioles ("collagen (vascular) diseases (M30-M36)")
• Type 2 Excludes: J82 Pulmonary eosinophilia, not elsewhere classified ("pulmonary eosinophilia due to systemic connective tissue disorders (M30-M36)")
• Code First: J84.170 Interstitial lung disease with progressive fibrotic phenotype in diseases classified elsewhere ("systemic connective tissue disorders (M30-M36)")
• Type 1 Excludes: L94 Other localized connective tissue disorders ("systemic connective tissue disorders (M30-M36)")

Diagnosis Index entries for M35.1

• Disease, diseased › mixed connective tissue
• Syndrome › connective tissue › overlap NEC

Nearby codes

• M35.08 Sjogren syndrome with gastrointestinal involvement
• M35.0A Sjogren syndrome with glomerular disease
• M35.0B Sjogren syndrome with vasculitis
• M35.0C Sjogren syndrome with dental involvement
• M35.09 Sjogren syndrome with other organ involvement
• M35.1 Other overlap syndromes (this code)
• M35.2 Behcet's disease
• M35.3 Polymyalgia rheumatica
• M35.4 Diffuse (eosinophilic) fasciitis
• M35.5 Multifocal fibrosclerosis
• M35.6 Relapsing panniculitis [Weber-Christian]