ICD-10-CM Code For Combined Immunodeficiencies: Group Overview

The International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM) code group D81 includes primary combined immunodeficiency disorders characterized by defects in both cellular and humoral immunity, such as severe combined immunodeficiency and related genetic immunodeficiencies. These ICD-10-CM diagnosis codes are used to document patients with recurrent, severe, or opportunistic infections and to capture disease severity, organ involvement, and immune system compromise. Accurate coding within the ICD-10-CM D81 group supports appropriate claim adjudication, complete clinical documentation, and correct reimbursement for complex immunology care.

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ICD-10-CM D81: Combined Immunodeficiencies Overview

The ICD-10-CM D81 group covers combined immunodeficiencies, which are primary disorders of the immune system characterized by defects in both cellular and humoral immunity. These conditions affect the adaptive immune response and increase susceptibility to recurrent, severe, or unusual infections. Accurate coding is important for documenting clinical complexity and supporting appropriate reimbursement for treatments and services.

When to Use

Use a code from this group when a patient has a documented combined immunodeficiency diagnosis confirmed by clinical findings, immunologic testing, or genetic testing. Codes are selected to reflect the specific disorder and any associated complications, manifestations, or organ involvement.

ICD-10-CM Codes

17 rows

ICD-10-CM Code	Description
D81.0	Severe combined immunodeficiency [SCID] with reticular dysgenesis
D81.1	Severe combined immunodeficiency [SCID] with low T- and B-cell numbers
D81.2	Severe combined immunodeficiency [SCID] with low or normal B-cell numbers
D81.30	Adenosine deaminase deficiency, unspecified
D81.31	Severe combined immunodeficiency due to adenosine deaminase deficiency
D81.32	Adenosine deaminase 2 deficiency
D81.39	Other adenosine deaminase deficiency
D81.4	Nezelof's syndrome
D81.5	Purine nucleoside phosphorylase [PNP] deficiency
D81.6	Major histocompatibility complex class I deficiency
D81.7	Major histocompatibility complex class II deficiency
D81.810	Biotinidase deficiency
D81.818	Other biotin-dependent carboxylase deficiency
D81.819	Biotin-dependent carboxylase deficiency, unspecified
D81.82	Activated Phosphoinositide 3-kinase Delta Syndrome [APDS]
D81.89	Other combined immunodeficiencies
D81.9	Combined immunodeficiency, unspecified

DRG Codes

6 rows

DRG Code	Description
640	Miscellaneous Disorders of Nutrition, Metabolism, Fluids and Electrolytes with MCC
641	Miscellaneous Disorders of Nutrition, Metabolism, Fluids and Electrolytes without MCC
642	Inborn and Other Disorders of Metabolism
808	Major Hematological and Immunological Diagnoses Except Sickle Cell Crisis and Coagulation Disorders with MCC
809	Major Hematological and Immunological Diagnoses Except Sickle Cell Crisis and Coagulation Disorders with CC
810	Major Hematological and Immunological Diagnoses Except Sickle Cell Crisis and Coagulation Disorders without CC/MCC

Typical Clinical Scenarios

A previously healthy infant presents in the emergency department with recurrent severe viral and opportunistic infections (persistent candidiasis, chronic diarrhea, failure to thrive) beginning in the first months of life; immunologic workup shows markedly low T-cell function with normal B-cell numbers, prompting evaluation for a combined T- and B-cell immunodeficiency such as severe combined immunodeficiency. A diagnosis from this group is assigned for congenital, severe combined T- and B-cell immunodeficiency identified on newborn/infant evaluation. Typical codes: D81.0, D81.1
A school-aged child with recurrent sinopulmonary bacterial infections and poor response to routine vaccinations is found on immunologic testing to have defective cellular and humoral immunity consistent with combined immunodeficiency not specified as severe; the family is referred for genetic testing and chronic immunologic management. A code from this group is used to document the chronic primary combined immunodeficiency as the underlying cause of recurrent infections and need for long-term immune follow-up. Typical codes: D81.32, D81.39
An adult with known combined immunodeficiency who undergoes stem cell transplant develops graft-versus-host complications and presents with opportunistic infections and worsening immune dysfunction requiring inpatient management; the combined immunodeficiency is recorded as a comorbidity influencing treatment and prognosis. Typical codes: D81.819, D81.89}

ICD-10-CM Code For Immunodeficiency With Predominantly Antibody Defects: Group Overview

D82-IMMUNODEFICIENCY-WITH-MAJOR-DEFECTS

ICD-10-CM Code For Immunodeficiency Associated With Other Major Defects: Group Overview

D83-COMMON-VARIABLE-IMMUNODEFICIENCY

ICD-10-CM Code For Common Variable Immunodeficiency: Group Overview

D84-OTHER-IMMUNODEFICIENCIES

ICD-10-CM Code For Other Immunodeficiencies: Group Overview

D86-SARCOIDOSIS

ICD-10-CM Code For Sarcoidosis: Group Overview

D89-OTHER-IMMUNE-MECHANISM-DISORDERS

ICD-10-CM Code For Other Disorders Involving The Immune Mechanism Not Elsewhere Classified: Group Overview

Frequently Asked Questions

References

1.CPT® Codes and Descriptions. AAPC. Retrieved Aug 11, 2026.Maintains the CPT code set's official descriptions and guidelines, licensed from the American Medical Association, used as the definitional source for CPT codes on this page.
2.HCPCS Quarterly Update. Centers for Medicare & Medicaid Services (CMS). Retrieved Aug 11, 2026.CMS's quarterly release of HCPCS Level II codes and short/long descriptors, the source for HCPCS code definitions and update history.
3.ICD-10-CM Full Code List. Centers for Medicare & Medicaid Services (CMS). Retrieved Aug 11, 2026.CMS's complete ICD-10-CM diagnosis code list, used to cross-reference diagnosis codes associated with this procedure or service.

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When to Use

ICD-10-CM Codes

17 rows

ICD-10-CM Code	Description
D81.0	Severe combined immunodeficiency [SCID] with reticular dysgenesis
D81.1	Severe combined immunodeficiency [SCID] with low T- and B-cell numbers
D81.2	Severe combined immunodeficiency [SCID] with low or normal B-cell numbers
D81.30	Adenosine deaminase deficiency, unspecified
D81.31	Severe combined immunodeficiency due to adenosine deaminase deficiency
D81.32	Adenosine deaminase 2 deficiency
D81.39	Other adenosine deaminase deficiency
D81.4	Nezelof's syndrome
D81.5	Purine nucleoside phosphorylase [PNP] deficiency
D81.6	Major histocompatibility complex class I deficiency
D81.7	Major histocompatibility complex class II deficiency
D81.810	Biotinidase deficiency
D81.818	Other biotin-dependent carboxylase deficiency
D81.819	Biotin-dependent carboxylase deficiency, unspecified
D81.82	Activated Phosphoinositide 3-kinase Delta Syndrome [APDS]
D81.89	Other combined immunodeficiencies
D81.9	Combined immunodeficiency, unspecified

DRG Codes

6 rows

DRG Code	Description
640	Miscellaneous Disorders of Nutrition, Metabolism, Fluids and Electrolytes with MCC
641	Miscellaneous Disorders of Nutrition, Metabolism, Fluids and Electrolytes without MCC
642	Inborn and Other Disorders of Metabolism
808	Major Hematological and Immunological Diagnoses Except Sickle Cell Crisis and Coagulation Disorders with MCC
809	Major Hematological and Immunological Diagnoses Except Sickle Cell Crisis and Coagulation Disorders with CC
810	Major Hematological and Immunological Diagnoses Except Sickle Cell Crisis and Coagulation Disorders without CC/MCC

Typical Clinical Scenarios

A previously healthy infant presents in the emergency department with recurrent severe viral and opportunistic infections (persistent candidiasis, chronic diarrhea, failure to thrive) beginning in the first months of life; immunologic workup shows markedly low T-cell function with normal B-cell numbers, prompting evaluation for a combined T- and B-cell immunodeficiency such as severe combined immunodeficiency. A diagnosis from this group is assigned for congenital, severe combined T- and B-cell immunodeficiency identified on newborn/infant evaluation. Typical codes: D81.0, D81.1
A school-aged child with recurrent sinopulmonary bacterial infections and poor response to routine vaccinations is found on immunologic testing to have defective cellular and humoral immunity consistent with combined immunodeficiency not specified as severe; the family is referred for genetic testing and chronic immunologic management. A code from this group is used to document the chronic primary combined immunodeficiency as the underlying cause of recurrent infections and need for long-term immune follow-up. Typical codes: D81.32, D81.39
An adult with known combined immunodeficiency who undergoes stem cell transplant develops graft-versus-host complications and presents with opportunistic infections and worsening immune dysfunction requiring inpatient management; the combined immunodeficiency is recorded as a comorbidity influencing treatment and prognosis. Typical codes: D81.819, D81.89}

ICD-10-CM Code For Immunodeficiency With Predominantly Antibody Defects: Group Overview

D82-IMMUNODEFICIENCY-WITH-MAJOR-DEFECTS

ICD-10-CM Code For Immunodeficiency Associated With Other Major Defects: Group Overview

D83-COMMON-VARIABLE-IMMUNODEFICIENCY

ICD-10-CM Code For Common Variable Immunodeficiency: Group Overview

D84-OTHER-IMMUNODEFICIENCIES

ICD-10-CM Code For Other Immunodeficiencies: Group Overview

D86-SARCOIDOSIS

ICD-10-CM Code For Sarcoidosis: Group Overview

D89-OTHER-IMMUNE-MECHANISM-DISORDERS

ICD-10-CM Code For Other Disorders Involving The Immune Mechanism Not Elsewhere Classified: Group Overview

Frequently Asked Questions

References

1.CPT® Codes and Descriptions. AAPC. Retrieved Aug 11, 2026.Maintains the CPT code set's official descriptions and guidelines, licensed from the American Medical Association, used as the definitional source for CPT codes on this page.
2.HCPCS Quarterly Update. Centers for Medicare & Medicaid Services (CMS). Retrieved Aug 11, 2026.CMS's quarterly release of HCPCS Level II codes and short/long descriptors, the source for HCPCS code definitions and update history.
3.ICD-10-CM Full Code List. Centers for Medicare & Medicaid Services (CMS). Retrieved Aug 11, 2026.CMS's complete ICD-10-CM diagnosis code list, used to cross-reference diagnosis codes associated with this procedure or service.

Published by

Trek Health powers OpenPayer with a leading commercial payer intelligence platform, seamlessly converting fragmented payer data into actionable insights for provider organizations.

ICD-10-CM Code For Combined Immunodeficiencies: Group Overview

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ICD-10-CM D81: Combined Immunodeficiencies Overview

ICD-10-CM Code For Combined Immunodeficiencies: Group Overview

Sign up for ICD-10-CM Code For Combined Immunodeficiencies: Group Overview policy alerts

ICD-10-CM D81: Combined Immunodeficiencies Overview

When to Use

ICD-10-CM Codes

DRG Codes

Typical Clinical Scenarios

Related Codes

References

When to Use

ICD-10-CM Codes

DRG Codes

Typical Clinical Scenarios

Related Codes

References

ICD-10-CM Code For Combined Immunodeficiencies: Group Overview

Sign up for ICD-10-CM Code For Combined Immunodeficiencies: Group Overview policy alerts

ICD-10-CM D81: Combined Immunodeficiencies Overview

ICD-10-CM Code For Combined Immunodeficiencies: Group Overview

Sign up for ICD-10-CM Code For Combined Immunodeficiencies: Group Overview policy alerts

ICD-10-CM D81: Combined Immunodeficiencies Overview

When to Use

ICD-10-CM Codes

DRG Codes

Typical Clinical Scenarios

Related Codes

Which ICD-10-CM codes are included in the D81 combined immunodeficiencies group?

What clinical features support using a D81 code for a patient?

How does accurate coding in D81 affect reimbursement and claims?

Are there related DRGs to consider when coding D81 diagnoses?

Which D81 codes represent adenosine deaminase and biotin-related deficiencies?

References

When to Use

ICD-10-CM Codes

DRG Codes

Typical Clinical Scenarios

Related Codes

Which ICD-10-CM codes are included in the D81 combined immunodeficiencies group?

What clinical features support using a D81 code for a patient?

How does accurate coding in D81 affect reimbursement and claims?

Are there related DRGs to consider when coding D81 diagnoses?

Which D81 codes represent adenosine deaminase and biotin-related deficiencies?

References