ICD-10-CM 2027
ICD-10 code for simian B disease
From the official ICD-10-CM alphabetic index entry “Disease, diseased › simian B”. Page updated September 29, 2026.
About coding simian B disease
The ICD-10-CM code for simian B disease is B00.4 (Herpesviral encephalitis).
Within B00 (herpesviral [herpes simplex] infections), B00.4 is specifically for herpesviral encephalitis. Related codes cover eczema herpeticum (B00.0), herpesviral vesicular dermatitis (B00.1), herpesviral gingivostomatitis and pharyngotonsillitis (B00.2), herpesviral meningitis (B00.3), herpesviral ocular disease (B00.5), disseminated herpesviral disease (B00.7), other forms of herpesviral infections (B00.8) and herpesviral infection, unspecified (B00.9).
Don't report B00.4 together with the conditions in its Excludes1 note: herpesviral encephalitis due to herpesvirus 6 and 7 (B10.01, B10.09) and non-simplex herpesviral encephalitis (B10.0-).
As a secondary diagnosis it is an MCC (major complication or comorbidity), which can move an inpatient stay into the highest-paying "with MCC" MS-DRG of its family, unless the principal diagnosis excludes it.
Don't confuse with (Excludes1 for B00.4)
Common questions about simian B disease ICD-10 codes
What is the ICD-10 code for simian B disease?
- B00.4 — Herpesviral encephalitis.
Is B00.4 billable?
- Yes. B00.4 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can B00.4 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict B00.4 as a principal diagnosis.
Is B00.4 a CC or MCC?
- B00.4 is an MCC (major complication or comorbidity) under MS-DRG v44.0, unless excluded by the principal diagnosis.