B08.21 — Exanthema subitum [sixth disease] due to human herpesvirus 6
Is B08.21 billable?
Yes — B08.21 is billable for FY2027. B08.21 is a valid, billable ICD-10-CM code at the highest level of specificity in its branch. B08.21 may be submitted for encounters from October 1, 2026 through September 30, 2027.
B08.21 at a glance
| Code | B08.21 |
|---|---|
| Description | Exanthema subitum [sixth disease] due to human herpesvirus 6 |
| Billable | Yes |
| Code set | ICD-10-CM FY2027 |
| Valid for encounters | October 1, 2026 – September 30, 2027 |
Which MS-DRGs does B08.21 group to?
B08.21 sits in MDC 15 and helps define the logic of 1 MS-DRG (version 44, FY2027). Which one a stay actually groups to also depends on procedures and secondary diagnoses.
- 791Prematurity with Major Problemsmedical
How is B08.21 listed in the Alphabetic Index?
These are the routes through the Alphabetic Index that lead to B08.21. They show the wording a clinician may have documented, which often differs from the Tabular description.
- Sixth disease › due to human herpesvirus 6
- Disease, diseased › sixth › due to human herpesvirus 6
- Exanthem, exanthema › subitum › due to human herpesvirus 6
- Roseola › infantum › due to human herpesvirus 6
Inclusion terms
Alternative wording in documentation that is classified to B08.21.
- Roseola infantum due to human herpesvirus 6
Excludes1 — never code together — inherited from B08
The conditions below can never be reported together with B08.21 on the same claim. An Excludes1 note means the two conditions cannot occur in the same patient, so reporting both is a coding error.
- vesicular stomatitis virus disease (A93.8)
Use additional code — inherited from Chapter 1
Report an additional code alongside B08.21 to fully describe the condition. B08.21 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 B08.21, but a patient may have both at the same time. When documentation supports it, B08.21 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 B08.21 existed?
B08.21 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.