D89.9 Disorder involving the immune mechanism, unspecified

Billable ICD-10-CM code, FY2026.

Applicable to

• Immune disease NOS

Applies from D89 Other disorders involving the immune mechanism, not elsewhere classified

Excludes1 (never code together)

• hyperglobulinemia NOS (R77.1)
• monoclonal gammopathy (of undetermined significance) (D47.2)

Excludes2 (not included here)

• transplant failure and rejection (T86.-)

Risk adjustment (HCC)

• CMS-HCC V22: HCC 47 — Disorders of Immunity
• RxHCC V08: HCC 99 — Immune Disorders
• ESRD V24: HCC 47

MS-DRG index

Defines the logic of DRG(s) 814-816 in MDC 16.

Approximate ICD-9-CM (GEMs)

• 279.9 Unspecified disorder of immune mechanism

Code annotations containing back-references to D89.9

Back-references to D89

• Type 1 Excludes: D72 Other disorders of white blood cells ("immunity disorders (D80-D89)")

Diagnosis Index entries for D89.9

• Disease, diseased › immune
• Disorder (of) › immune mechanism (immunity)

Nearby codes

• D89.834 Cytokine release syndrome, grade 4
• D89.835 Cytokine release syndrome, grade 5
• D89.839 Cytokine release syndrome, grade unspecified
• D89.84 IgG4-related disease
• D89.89 Other specified disorders involving the immune mechanism, not elsewhere classified
• D89.9 Disorder involving the immune mechanism, unspecified (this code)