ICD-10 Code D89.89 – Other specified disorders involving the immune mechanism, not elsewhere classified (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code D89.89 – Other specified disorders involving the immune mechanism, not elsewhere classified
What it is
D89.89 is used for immune mechanism disorders that do not fit a more specific ICD-10 category. It captures a documented immune-related condition when the record names a distinct disorder but not a better code.
Clinical signs
Clinical features vary; refer to documentation. You may see immune dysregulation, unusual inflammatory findings, or other signs that support an immune mechanism disorder without a more specific diagnosis.
When to use this code
Use this code when the provider documents a specified immune mechanism disorder and no other ICD-10 code describes it better. It is appropriate for clearly identified immune-related conditions that remain nonspecific in the classification. Check documentation if the record only says “immune disorder” without detail.
Do not use for
Do not use D89.89 for common autoimmune diseases, immunodeficiency states, or plasma cell disorders when a more specific code is available. Avoid it when the chart supports a different, named diagnosis.
Coding tip
Code D89.89 only after confirming the provider’s exact wording and ruling out a more specific immune disorder code.