ICD-10-CM 2027
ICD-10 code for thymus dysfunction
From the official ICD-10-CM alphabetic index entry “Dysfunction › thymus”. Page updated September 29, 2026.
About coding thymus dysfunction
The ICD-10-CM code for thymus dysfunction is E32.9 (Disease of thymus, unspecified).
Within E32, choose E32.9 (Disease of thymus, unspecified) only when documentation doesn't support a more specific option: persistent hyperplasia of thymus (E32.0), abscess of thymus (E32.1) and other diseases of thymus (E32.8).
It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.
In MS-DRG v44.0, it is part of the grouping logic for DRG 814 (Reticuloendothelial and Immunity Disorders with MCC, relative weight 2.0729), DRG 815 (Reticuloendothelial and Immunity Disorders with CC, relative weight 1.0444) and DRG 816 (Reticuloendothelial and Immunity Disorders without CC/MCC, relative weight 0.7381), 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.
Common questions about thymus dysfunction ICD-10 codes
What is the ICD-10 code for thymus dysfunction?
- E32.9 — Disease of thymus, unspecified.
Is E32.9 billable?
- Yes. E32.9 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can E32.9 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict E32.9 as a principal diagnosis.
Is E32.9 a CC or MCC?
- No. E32.9 is neither a CC nor an MCC under MS-DRG v44.0.