B09 — Unspecified viral infection characterized by skin and mucous membrane lesions
Is B09 billable?
Yes, but B09 is an unspecified code. B09 is a valid, billable ICD-10-CM code for encounters from October 1, 2026 through September 30, 2027. However, B09 is an unspecified or catch-all code. Payers apply additional scrutiny to unspecified codes and many deny them when the medical record supports a more specific option, so check the documentation before selecting B09.
B09 at a glance
| Code | B09 |
|---|---|
| Description | Unspecified viral infection characterized by skin and mucous membrane lesions |
| Billable | Yes |
| Code set | ICD-10-CM FY2027 |
| Valid for encounters | October 1, 2026 – September 30, 2027 |
Which MS-DRGs does B09 group to?
B09 sits in MDC 18 and helps define the logic of 2 MS-DRGs (version 44, FY2027). Which one a stay actually groups to also depends on procedures and secondary diagnoses.
- 865Viral Illness with MCCmedical
- 866Viral Illness without MCCmedical
How is B09 listed in the Alphabetic Index?
These are the routes through the Alphabetic Index that lead to B09. They show the wording a clinician may have documented, which often differs from the Tabular description.
- Enanthema, viral
- Roseola
- Encephalitis › postexanthematous NEC (chronic) (hemorrhagic) (idiopathic) (nonepidemic) (spurious) (subacute)
- Exanthem, exanthema › viral, virus
- Keratoconjunctivitis › in exanthema
- Infection, infected, infective › virus, viral NOS › exanthem NOS (opportunistic)
- Keratitis › in › exanthema (nodular) (nonulcerative) (simple) (zonular)
Inclusion terms
Alternative wording in documentation that is classified to B09.
- Viral enanthema NOS
- Viral exanthema NOS
Use additional code — inherited from Chapter 1
Report an additional code alongside B09 to fully describe the condition. B09 is sequenced first.
- code to identify resistance to antimicrobial drugs (Z16.-)
Excludes2 — not included here — inherited from Chapter 1
The conditions below are not part of B09, but a patient may have both at the same time. When documentation supports it, B09 and the excluded code may both be reported.
- carrier or suspected carrier of infectious disease (Z22.-)
- certain localized infections - see body system-related chapters
- infectious and parasitic diseases complicating pregnancy, childbirth and the puerperium (O98.-)
- infectious and parasitic diseases specific to the perinatal period (P35-P39)
- influenza and other acute respiratory infections (J00-J22)
How long has B09 existed?
B09 has been in ICD-10-CM since at least FY2016, the earliest fiscal year on record here.
Derived from the official order files for FY2016–FY2026. FY2017 and FY2020 publish no order file, so those years are not covered.