ICD-10 Code D89.8 – Other specified disorders involving the immune mechanism, not elsewhere classified (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code D89.8 – Other specified disorders involving the immune mechanism, not elsewhere classified
What it is
D89.8 is used for immune mechanism disorders that do not fit a more specific ICD-10-CM category. Use it when the record identifies an immune-related condition, but the documentation does not support a more precise code.
Clinical signs
Clinical features vary; refer to documentation. Records may describe immune dysfunction, abnormal immune responses, or another specified immune disorder without a clearer classification.
When to use this code
Use D89.8 when the clinician documents a specified immune mechanism disorder and no more specific code is available. It is appropriate when the chart supports an immune-related diagnosis, but the exact subtype is not named. Check documentation before assigning it.
Do not use for
Do not use this code for broader, unspecified immune disorders when a more exact diagnosis is documented. Avoid it if the condition is better classified elsewhere in ICD-10-CM; check documentation.
Coding tip
Look for the most specific immune disorder term in the note before defaulting to D89.8.