B03 — Smallpox
Is B03 billable?
Yes — B03 is billable for FY2027. B03 is a valid, billable ICD-10-CM code at the highest level of specificity in its branch. B03 may be submitted for encounters from October 1, 2026 through September 30, 2027.
B03 at a glance
| Code | B03 |
|---|---|
| Description | Smallpox |
| Billable | Yes |
| Code set | ICD-10-CM FY2027 |
| Valid for encounters | October 1, 2026 – September 30, 2027 |
Which MS-DRGs does B03 group to?
B03 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
As a secondary diagnosis, B03 is a complication or comorbidity (CC), which can move a stay into a higher-paying DRG.
How is B03 listed in the Alphabetic Index?
These are the routes through the Alphabetic Index that lead to B03. They show the wording a clinician may have documented, which often differs from the Tabular description.
- Alastrim
- Smallpox
- Variola (major) (minor)
- Varioloid
Note
- In 1980 the 33rd World Health Assembly declared that smallpox had been eradicated.
- The classification is maintained for surveillance purposes.
Use additional code — inherited from Chapter 1
Report an additional code alongside B03 to fully describe the condition. B03 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 B03, but a patient may have both at the same time. When documentation supports it, B03 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 B03 existed?
B03 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.