Combined immunodeficiencies
In Certain disorders involving the immune mechanism (D80-D89), chapter 3: Diseases of the Blood and Blood-Forming Organs
17 billable codes under D81: 14 are a CC; 14 map to HCC 114 (Common Variable and Combined Immunodeficiencies), HCC 115 (Specified Immunodeficiencies and White Blood Cell Disorders).A CC or MCC (major CC) is a secondary diagnosis that raises the MS-DRG payment. An HCC counts toward a Medicare Advantage patient's risk score.
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Instructional notes
Excludes1: not coded here, use a different code
- autosomal recessive agammaglobulinemia (Swiss type) (D80.0)
Also applies, from Certain disorders involving the immune mechanism (D80-D89)
These notes sit on D80-D89 and apply to every code under it, including D81.
Includes: conditions that are coded here
- defects in the complement system
- immunodeficiency disorders, except human immunodeficiency virus [HIV] disease
- sarcoidosis
Excludes1: not coded here, use a different code
Excludes2: not included here, code separately if applicable
- human immunodeficiency virus [HIV] disease (B20)
Official coding guidelines
From the ICD-10-CM Official Guidelines for Coding and Reporting, FY 2027 (CMS and NCHS). Links open the PDF at the right page.
There are no chapter-specific rules for Chapter 3 yet, so the general rules in Section I.B apply.
All codes under D81
D81 can't be used on a claim. Pick a billable code below; grey headings group them.
- D81.0Severe combined immunodeficiency [SCID] with reticular dysgenesis
- D81.1Severe combined immunodeficiency [SCID] with low T- and B-cell numbers
- D81.2Severe combined immunodeficiency [SCID] with low or normal B-cell numbers
- D81.3Adenosine deaminase [ADA] deficiency
- D81.30Adenosine deaminase deficiency, unspecified
- D81.31Severe combined immunodeficiency due to adenosine deaminase deficiency
- D81.32Adenosine deaminase 2 deficiency
- D81.39Other adenosine deaminase deficiency
- D81.4Nezelof's syndrome
- D81.5Purine nucleoside phosphorylase [PNP] deficiency
- D81.6Major histocompatibility complex class I deficiency
- D81.7Major histocompatibility complex class II deficiency
- D81.8Other combined immunodeficiencies
- D81.81Biotin-dependent carboxylase deficiency
- D81.810Biotinidase deficiency
- D81.818Other biotin-dependent carboxylase deficiency
- D81.819Biotin-dependent carboxylase deficiency, unspecified
- D81.82Activated Phosphoinositide 3-kinase Delta Syndrome [APDS]
- D81.89Other combined immunodeficiencies
- D81.9Combined immunodeficiency, unspecified
D81 MS-DRGs
As the principal diagnosis, the billable codes under D81 group to MS-DRG 808, 809, 810, 642, 640, or 641 (v44.0). Which one applies depends on procedures performed, secondary diagnoses (CC/MCC), and the patient's age and discharge status.
- DRG 808 Major Hematological and Immunological Diagnoses Except Sickle Cell Crisis and Coagulation Disorders with MCC (9 of 17 codes)
- DRG 809 Major Hematological and Immunological Diagnoses Except Sickle Cell Crisis and Coagulation Disorders with CC (9 of 17 codes)
- DRG 810 Major Hematological and Immunological Diagnoses Except Sickle Cell Crisis and Coagulation Disorders without CC/MCC (9 of 17 codes)
- DRG 642 Inborn and Other Disorders of Metabolism (6 of 17 codes)
- DRG 640 Miscellaneous Disorders of Nutrition, Metabolism, Fluids and Electrolytes with MCC (2 of 17 codes)
- DRG 641 Miscellaneous Disorders of Nutrition, Metabolism, Fluids and Electrolytes without MCC (2 of 17 codes)
Other codes that refer to D81
Notes on these codes point to D81.
- E79 Excludes1: combined immunodeficiency disorders (D81.-)
Code history
Valid since FY2016, when ICD-10-CM took effect on October 1, 2015. No changes since.