ICD-10 Code for Collagenosis

The default ICD-10-CM 2027 code for collagenosis, collagen disease (nonvascular) (vascular) is M35.9 – Systemic involvement of connective tissue, unspecified. More specific codes depend on the details documented, as listed in the official index (4 codes, 4 billable).

Main code
M35.9 – Systemic involvement of connective tissue, unspecified
Billable
Yes

Index entries for Collagenosis

How to choose the right code

Start with the main term, then pick the indented subterm that matches the documentation (type, cause, site, laterality, episode of care). Always confirm the code in the tabular list: follow its Excludes1/Excludes2, “code first” and “use additional code” notes, and add a 7th character where required.

Source: CDC/NCHS ICD-10-CM FY2027 alphabetic index.