ICD-10-CM 2027
ICD-10 code for cytomegalovirus infection
From the official ICD-10-CM alphabetic index entry “Cytomegalovirus infection”. Page updated September 29, 2026.
About coding cytomegalovirus infection
The ICD-10-CM code for cytomegalovirus infection is B25.9 (Cytomegaloviral disease, unspecified).
Within B25, choose B25.9 (unspecified) only when documentation doesn't support a more specific option: cytomegaloviral pneumonitis (B25.0), cytomegaloviral hepatitis (B25.1), cytomegaloviral pancreatitis (B25.2) and other cytomegaloviral diseases (B25.8).
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 865 (Viral Illness with MCC, relative weight 1.3485), DRG 866 (Viral Illness without MCC, relative weight 0.8692), DRG 974 (HIV with Major Related Condition with MCC, relative weight 3.0506), DRG 975 (HIV with Major Related Condition with CC, relative weight 1.3252) and DRG 976 (HIV with Major Related Condition without CC/MCC, relative weight 0.8124), in MDC 18 (Infectious and Parasitic Diseases, Systemic or Unspecified Sites) and MDC 25 (Human Immunodeficiency Virus Infections), 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 cytomegalovirus infection ICD-10 codes
What is the ICD-10 code for cytomegalovirus infection?
- B25.9 — Cytomegaloviral disease, unspecified.
Is B25.9 billable?
- Yes. B25.9 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can B25.9 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict B25.9 as a principal diagnosis.
Is B25.9 a CC or MCC?
- B25.9 is a CC (complication or comorbidity) under MS-DRG v44.0, unless excluded by the principal diagnosis.