ICD-10 D84.81
Billable / Specific HCC v28: 47 CCImmunodeficiency due to conditions classified elsewhere
About ICD-10-CM D84.81
ICD-10-CM code D84.81 represents Immunodeficiency due to conditions classified elsewhere. This is a billable/specific code in the Blood and Blood-forming Organs chapter (block D84). The 2026 edition of ICD-10-CM D84.81 became effective on October 1, 2025.
Coding Tips for D84.81
Specialist guidance from the PayerReady Medical Coding Team. Specificity warnings, HCC capture rules, sequencing notes.
D84.81 is a CMS-HCC v28 risk-adjustment code (category 47). To count for the patient Risk Adjustment Factor (RAF), document the diagnosis with MEAT language each calendar year: Monitored, Evaluated, Assessed, Treated. A diagnosis on the problem list alone does not satisfy CMS RADV audit standards. Include the diagnosis in the assessment with current status and current treatment plan.
D84.81 is designated CC for MS-DRG grouping. On inpatient claims, this code can shift the DRG to the with-CC variant when documented as a present-on-admission secondary diagnosis. Hospital CDI programs flag CC opportunities during chart review. Failure to capture this code may leave 30 to 80 percent of the inpatient stay revenue unrealized.
Type 1 Excludes
Pure excludes, these codes can never be coded together with D84.81. The conditions are mutually exclusive (e.g., congenital vs acquired forms).
- certain disorders involving the immune mechanism (D80-D83, D84.0, D84.1, D84.9)
- human immunodeficiency virus [HIV] disease (B20)
Coding Notes
Code First
- underlying condition, such as:
- chromosomal abnormalities (Q90-Q99)
- diabetes mellitus (E08-E13)
- malignant neoplasms (C00-C96)
Medicare Advantage HCC Impact
Capture this diagnosis annually for accurate risk adjustment. Missed HCC captures are the #1 revenue leak in Medicare Advantage risk programs.
Inpatient DRG Impact, CC
codes Immunodeficiency due to conditions classified elsewhere. As a Complication/Comorbidity (CC), this contributes to DRG severity adjustment when documented alongside the principal diagnosis.
Medicare LCD Coverage for D84.81
Local Coverage Determinations (LCDs) from CMS MACs that list D84.81 as a covered diagnosis.
Showing top 10 of 75 total . Click a CPT for full coverage scope.
Commercial Payer Coverage
Coverage policies from major commercial payers referencing D84.81.
5 Medicare
1 Aetna
CPT Codes Commonly Billed with D84.81
Procedures frequently paired with this diagnosis based on PayerReady's Dx↔Px linkage data.
- 87507 CMS LCD: Billing and Coding: Gastrointestinal Pathogen (GIP) Panels Utilizing Multiplex Nucleic Acid Amplification Techniques (NAATs) CMS LCD
- 87505 CMS LCD: Billing and Coding: Gastrointestinal Pathogen (GIP) Panels Utilizing Multiplex Nucleic Acid Amplification Techniques (NAATs) CMS LCD
- 87506 CMS LCD: Billing and Coding: Gastrointestinal Pathogen (GIP) Panels Utilizing Multiplex Nucleic Acid Amplification Techniques (NAATs) CMS LCD
Codes Adjacent To D84.81
Other codes in section D80-D89 (Certain disorders involving the immune mechanism).
ICD-10 D84.81, Billing FAQ
Is ICD-10 code D84.81 billable? +
Yes, D84.81 is a billable ICD-10-CM code that can appear as a primary or secondary diagnosis on claims.
What codes are Type 1 Excludes for D84.81? +
Type 1 Excludes (never code together with D84.81): certain disorders involving the immune mechanism (D80-D83, D84.0, D84.1, D84.9); human immunodeficiency virus [HIV] disease (B20)
Does D84.81 affect Medicare Advantage HCC risk adjustment? +
Yes. D84.81 maps to CMS-HCC v28 category 47. Capture this diagnosis annually for accurate Medicare Advantage risk score.
Is D84.81 a CC or MCC for inpatient DRG? +
Yes, this code is designated as CC. Documenting as a secondary diagnosis on inpatient claims can shift the DRG to a higher-weighted category.
What CPT codes are commonly billed with D84.81? +
Procedures frequently paired with D84.81 include: 87507, 87505, 87506.
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Reviewed by the PayerReady Medical Coding Team
Verified against the CMS 2026 code set on May 31, 2026.
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