A91 — Dengue hemorrhagic fever
Is A91 billable?
Yes — A91 is billable for FY2027. A91 is a valid, billable ICD-10-CM code at the highest level of specificity in its branch. A91 may be submitted for encounters from October 1, 2026 through September 30, 2027.
A91 at a glance
| Code | A91 |
|---|---|
| Description | Dengue hemorrhagic fever |
| Billable | Yes |
| Code set | ICD-10-CM FY2027 |
| Valid for encounters | October 1, 2026 – September 30, 2027 |
Which MS-DRGs does A91 group to?
A91 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, A91 is a complication or comorbidity (CC), which can move a stay into a higher-paying DRG.
How is A91 listed in the Alphabetic Index?
These are the routes through the Alphabetic Index that lead to A91. They show the wording a clinician may have documented, which often differs from the Tabular description.
- Bangkok hemorrhagic fever
- Singapore hemorrhagic fever
- Southeast Asian hemorrhagic fever
- Thailand hemorrhagic fever
- Dengue › hemorrhagic (classical) (fever)
- Fever › Bangkok hemorrhagic (inanition) (of unknown origin) (persistent) (with chills) (with rigor)
- Fever › Philippine hemorrhagic (inanition) (of unknown origin) (persistent) (with chills) (with rigor)
- Fever › Singapore hemorrhagic (inanition) (of unknown origin) (persistent) (with chills) (with rigor)
- Fever › Southeast Asia hemorrhagic (inanition) (of unknown origin) (persistent) (with chills) (with rigor)
- Fever › Thailand hemorrhagic (inanition) (of unknown origin) (persistent) (with chills) (with rigor)
- Fever › dengue › hemorrhagic (inanition) (of unknown origin) (persistent) (with chills) (with rigor)
- Fever › hemorrhagicNOS › Bangkok (inanition) (of unknown origin) (persistent) (with chills) (with rigor)
Use additional code — inherited from Chapter 1
Report an additional code alongside A91 to fully describe the condition. A91 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 A91, but a patient may have both at the same time. When documentation supports it, A91 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 A91 existed?
A91 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.
Which codes are confused with A91?
ICD-10-CM declares these codes mutually exclusive with A91 — exactly one of each pair can be correct for a given encounter.