D89.9 – Disorder involving the immune mechanism, unspecified

ICD-10-CM 2027 diagnosis code · Certain disorders involving the immune mechanism

Billable code

ICD-10-CM code D89.9
Code
D89.9 (claims format: D899)
Description
Disorder involving the immune mechanism, unspecified
Billable
Yes – valid for HIPAA-covered transactions
Valid for
Dates of service October 1, 2026 – September 30, 2027 (FY2027)
Chapter
3. Diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism (D50-D89)
Block
D80-D89 Certain disorders involving the immune mechanism
Parent codes
D89

Notes for D89.9

Applicable to:
  • Immune disease NOS

Notes inherited from parent codes

Instructional notes at a category or block level apply to every code below it.

D89 – Other disorders involving the immune mechanism, not elsewhere classified

Excludes1 (not coded here):
  • hyperglobulinemia NOS (R77.1)
  • monoclonal gammopathy (of undetermined significance) (D47.2)
Excludes2 (not included here):
  • transplant failure and rejection (T86.-)

Block D80-D89

Includes:
  • defects in the complement system
  • immunodeficiency disorders, except human immunodeficiency virus [HIV] disease
  • sarcoidosis
Excludes1 (not coded here):
  • autoimmune disease (systemic) NOS (M35.9)
  • functional disorders of polymorphonuclear neutrophils (D71-)
Excludes2 (not included here):
  • human immunodeficiency virus [HIV] disease (B20)

Index terms for D89.9

Entries in the ICD-10-CM alphabetic index that lead to this code:

Related codes in D89

Frequently asked questions

What is ICD-10 code D89.9?

D89.9 is the ICD-10-CM code for disorder involving the immune mechanism, unspecified, in the block D80-D89 (Certain disorders involving the immune mechanism).

Is D89.9 a billable code?

Yes. D89.9 is a billable/specific code that can be used to indicate a diagnosis for reimbursement purposes.

What category does D89.9 belong to?

It belongs to category D89 – Other disorders involving the immune mechanism, not elsewhere classified.

Source: CDC/NCHS ICD-10-CM FY2027 code files, tabular list and index. Reference only – code assignment must follow the official ICD-10-CM guidelines and documentation in the medical record.