M35.9
Systemic involvement of connective tissue, unspecified
Billable FY2026 2025-10-01 → 2026-09-30
This is the unspecified option. 9 more
specific codes sit alongside it. Worth
checking whether the documentation supports one of them.
Exclusions 12 never code together
M30-M36block
Excludes1
- autoimmune disease, single organ or single cell-type -code to relevant condition category
M00-M99chapter
Excludes2
- arthropathic psoriasis (L40.5-)L40.5-
- certain conditions originating in the perinatal period (P04-P96)P04-P96
- certain infectious and parasitic diseases (A00-B99)A00-B99
- compartment syndrome (traumatic) (T79.A-)T79.A-
- complications of pregnancy, childbirth and the puerperium (O00-O9A)O00-O9A
- congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)Q00-Q99
- endocrine, nutritional and metabolic diseases (E00-E88)E00-E88
- injury, poisoning and certain other consequences of external causes (S00-T88)S00-T88
- neoplasms (C00-D49)C00-D49
- symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)R00-R94
Excludes1 — never code together. The excluded condition and this one are mutually exclusive.
Excludes2 — not included here, but the patient may have both. Code both when documented.
Instructional notes 7
M35.9code
Inclusion terms
- Autoimmune disease (systemic) NOS
- Collagen (vascular) disease NOS
M30-M36block
Includes
- autoimmune disease NOS
- collagen (vascular) disease NOS
- systemic autoimmune disease
- systemic collagen (vascular) disease
M00-M99chapter
Notes
- Use an external cause code following the code for the musculoskeletal condition, if applicable, to identify the cause of the musculoskeletal condition
Index entries leading here 8
- Ataxia, ataxy, ataxic R27.0
- gluten M35.9
- Autoimmune
- disease (systemic) M35.9
- Disease, diseased — see also Syndrome
- Collagenosis, collagen disease (nonvascular) (vascular) M35.9
- Polyneuropathy (peripheral) G62.9
- Syndrome — see also Disease
- connective tissue M35.9
- Dyscollagenosis M35.9
- Skin — see also condition
- hidebound M35.9
Alongside this code 9 same parent — M35
M35.0 Sjogren syndrome category M35.1 Other overlap syndromes M35.2 Behcet'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 category
Medications 4
245 Connective Tissue Diseases drugs 33 Neoplasms, Connective Tissue drugs 1331 Skin and Connective Tissue Diseases drugs 80 Neoplasms, Connective and Soft Tissue drugs
MED-RT files conditions by MeSH, which carves the world differently from ICD-10. These are name matches on this code's description, offered as candidates — not as an assertion that they are this code.
Additional references
AHA Coding Clinic® Licence required
Official coding advice for this code. Published by the American Hospital Association. Not included in this installation.