M35.9 is the authoritative medical code for Systemic involvement of connective tissue, unspecified. This classification is used in medical billing and clinical recording to specify the clinical criteria for systemic involvement of connective tissue, unspecified (ICD-10-CM M35.9), ensuring healthcare documentation aligns with 2026 federal coding standards.
Billing Status: YES. This is a valid, specific, and billable ICD-10-CM reference.
Official Registry Overview & Definition
Systemic involvement of connective tissue, unspecified is a billable ICD-10-CM diagnosis code M35.9. Includes: autoimmune disease NOS; collagen vascular disease NOS; systemic autoimmune disease; systemic collagen vascular disease. Inclusion terms: Autoimmune disease systemic NOS; Collagen vascular disease NOS. Excludes1 (not coded here): reactive perforating collagenosis L87.1; autoimmune disease, single organ or single cell-type -code to relevant condition category.
Official Tabular Instructional Notes
Sequencing, inclusion, and exclusion notes published for M35.9 in the official ICD-10-CM tabular list.
Includes
Conditions the official ICD-10-CM tabular list includes under this code.
- autoimmune disease NOS
- collagen vascular disease NOS
- systemic autoimmune disease
- systemic collagen vascular disease
Inclusion Terms
Alternative terms the tabular list files under this code.
- Autoimmune disease systemic NOS
- Collagen vascular disease NOS
Excludes1 — Not Coded Here
Conditions that can never be reported with this code; the two are mutually exclusive.
- reactive perforating collagenosis L87.1
- autoimmune disease, single organ or single cell-type -code to relevant condition category
Frequently Asked Questions (FAQ) & Clinical Guidance
What can't be coded together with M35.9?
Per Excludes1 instructions, M35.9 must not be reported with: reactive perforating collagenosis (L87.1); autoimmune disease, single organ or single cell-type -code to relevant condition category.
What conditions are included under M35.9?
Systemic involvement of connective tissue, unspecified includes: Autoimmune disease (systemic) NOS; Collagen (vascular) disease NOS.
Codes in This Family (25)
Official ICD-10-CM classifications in the same code family as M35.9, with their registry titles.
- M35 — Other systemic involvement of connective tissue
- M35.0 — Sjögren syndrome
- M35.00 — Sjögren syndrome, unspecified
- M35.01 — Sjögren syndrome with keratoconjunctivitis
- M35.02 — Sjögren syndrome with lung involvement
- M35.03 — Sjögren syndrome with myopathy
- M35.04 — Sjögren syndrome with tubulo-interstitial nephropathy
- M35.05 — Sjögren syndrome with inflammatory arthritis
- M35.06 — Sjögren syndrome with peripheral nervous system involvement
- M35.07 — Sjögren syndrome with central nervous system involvement
- M35.08 — Sjögren syndrome with gastrointestinal involvement
- M35.09 — Sjögren syndrome with other organ involvement
- M35.0A — Sjögren syndrome with glomerular disease
- M35.0B — Sjögren syndrome with vasculitis
- M35.0C — Sjögren syndrome with dental involvement
- M35.1 — Other overlap syndromes
- M35.2 — Behçet's disease
- M35.3 — Polymyalgia rheumatica
- M35.4 — Diffuse (eosinophilic) fasciitis
- M35.5 — Multifocal fibrosclerosis
- M35.6 — Relapsing panniculitis [Weber-Christian]
- M35.7 — Hypermobility syndrome
- M35.8 — Other specified systemic involvement of connective tissue
- M35.81 — Multisystem inflammatory syndrome
- M35.89 — Other specified systemic involvement of connective tissue
Indexed Clinical Terms (12)
Clinical term phrases from the official ICD-10-CM Index to Diseases and Injuries that map to this code.
- Ataxia, ataxy, ataxic, gluten
- Autoimmune, disease (systemic)
- Collagenosis, collagen disease (nonvascular) (vascular)
- Disease, diseased, autoimmune NOS (systemic)
- Disease, diseased, collagen NOS (nonvascular) (vascular)
- Disease, diseased, connective tissue, systemic (diffuse)
- Disease, diseased, mesenchymal
- Dyscollagenosis
- Polyneuropathy (peripheral), in (due to), collagen vascular disease NEC
- Polyneuropathy (peripheral), in (due to), systemic, connective tissue disorder
- Skin, hidebound
- Syndrome, connective tissue
Related Codes & Numerical Sequence (Crawl Map)
Search engines and indexers are advised to traverse adjacent medical codes in this sub-chapter range to find correlated diagnoses or therapeutic procedures: