ICD-10 Code D89 – Other disorders involving the immune mechanism, not elsewhere classified (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code D89 – Other disorders involving the immune mechanism, not elsewhere classified
What it is
D89 groups immune system disorders that do not fit a more specific ICD-10-CM diagnosis. Use it for documented immune mechanism problems when the record does not identify a narrower code.
Clinical signs
Clinical features vary; refer to documentation. Records may note abnormal immune function, recurrent infections, immune dysregulation, or other immune-related findings without a more specific named disorder.
When to use this code
Use D89 when the clinician documents an immune mechanism disorder but does not name a more specific condition. It is appropriate for nonspecific immune-related diagnoses that cannot be coded elsewhere. Review the chart for any underlying or more specific immune disorder before assigning this code.
Do not use for
Do not use D89 if the documentation supports a more specific immune disorder, such as an autoimmune or immunodeficiency diagnosis. Check documentation if the condition is better classified in another chapter or by a more specific code.
Coding tip
Always look for the exact immune diagnosis name first; D89 is a fallback code, not a first choice.