ICD-10 code for combined immunodeficiency

The ICD-10-CM code for combined immunodeficiency is D81.9 (Combined immunodeficiency, unspecified). The official index lists 9 more specific codes, so check the documentation for details such as type, cause, site or severity before settling on D81.9.

Within D81, choose D81.9 (Combined immunodeficiency, unspecified) only when documentation doesn't support a more specific option: severe combined immunodeficiency [SCID] with reticular dysgenesis (D81.0), severe combined immunodeficiency [SCID] with low T- and B-cell numbers (D81.1), severe combined immunodeficiency [SCID] with low or normal B-cell numbers (D81.2), adenosine deaminase [ADA] deficiency (D81.3), Nezelof's syndrome (D81.4), purine nucleoside phosphorylase [PNP] deficiency (D81.5), major histocompatibility complex class I deficiency (D81.6), major histocompatibility complex class II deficiency (D81.7) and 1 more.

As a secondary diagnosis it is a CC (complication or comorbidity), which can move an inpatient stay into the "with CC" MS-DRG of its family, unless the principal diagnosis excludes it.

In MS-DRG v44.0, it is part of the grouping logic for DRG 808 (Major Hematological and Immunological Diagnoses Except Sickle Cell Crisis and Coagulation Disorders with MCC, relative weight 2.1705), DRG 809 (Major Hematological and Immunological Diagnoses Except Sickle Cell Crisis and Coagulation Disorders with CC, relative weight 1.2262) and DRG 810 (Major Hematological and Immunological Diagnoses Except Sickle Cell Crisis and Coagulation Disorders without CC/MCC, relative weight 1.075), in MDC 16 (Diseases and Disorders of the Blood and Blood Forming Organs and Immunological Disorders), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.