D84.81

Immunodeficiency due to conditions classified elsewhere

FY2027Chapter 3: Diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism/D80–D89 Certain disorders involving the immune mechanism

BillableComplete code, valid to report

D84.81 (also written D8481) is a billable ICD-10-CM diagnosis code for immunodeficiency due to conditions classified elsewhere. It is part of the FY2027 code set, effective October 1, 2026. It is one of the 7 codes in category D84 (Other immunodeficiencies). The Alphabetic Index lists it under 1 entry. Its coding notes include a Code first instruction, 4 Excludes1 entries and 10 Excludes2 entries.

Code first

If the underlying condition listed here is present and known, sequence it first.

This code
  • underlying condition, such as:

Excludes1

Not coded here. The listed conditions generally should not be reported together.

This code
  • certain disorders involving the immune mechanism (D80-D83, D84.0, D84.1, D84.9)
  • human immunodeficiency virus [HIV] disease (B20)
Also from chapter/block level (2 notes)
Inherited from D80–D89 Certain disorders involving the immune mechanism
  • autoimmune disease (systemic) NOS (M35.9)
  • functional disorders of polymorphonuclear neutrophils (D71-)

Excludes2

Not included here. Both codes may be reported if the patient has both conditions.

Also from chapter/block level (10 notes)
Inherited from D80–D89 Certain disorders involving the immune mechanism
  • human immunodeficiency virus [HIV] disease (B20)
Inherited from Chapter 3 Diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism
  • autoimmune disease (systemic) NOS (M35.9)
  • certain conditions originating in the perinatal period (P00-P96)
  • complications of pregnancy, childbirth and the puerperium (O00-O9A)
  • congenital malformations, deformations and chromosomal abnormalities (Q00-Q99)
  • endocrine, nutritional and metabolic diseases (E00-E88)
  • human immunodeficiency virus [HIV] disease (B20)
  • injury, poisoning and certain other consequences of external causes (S00-T88)
  • neoplasms (C00-D49)
  • symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)

Care settings

How CMS programs treat this code. These are CMS claim edits and list entries, not coverage or eligibility rules.

Hospice: not accepted as primary

Not accepted as the principal diagnosis on a hospice claim (bill types 081x and 082x). The Integrated OCE returns an edit for this code.
Reason: Manifestation code. Report the underlying condition first (see the Code first note).

Source: CMS Integrated Outpatient Code Editor (IOCE) v27.3, effective October 1, 2026, edit 86

Hospital CC

Counts as a complication or comorbidity (CC) when reported as a secondary diagnosis on an inpatient claim. It does not count when the principal diagnosis is one of the 44 codes in its exclusion list. Some MS-DRGs also ignore a CC or MCC that defines the DRG.

Source: CMS MS-DRG Definitions Manual v44, effective October 1, 2026, Appendix C

Includes

Further defines or gives examples of the content of the category.

Also from chapter/block level (3 notes)
Inherited from D80–D89 Certain disorders involving the immune mechanism
  • defects in the complement system
  • immunodeficiency disorders, except human immunodeficiency virus [HIV] disease
  • sarcoidosis

Alphabetic Index terms

Terms the official Alphabetic Index lists for this code. 1 entry