Unspecified viral hemorrhagic fever
In Arthropod-borne viral fevers and viral hemorrhagic fevers (A90-A99), chapter 1: Certain Infectious and Parasitic Diseases
- A99 is an unspecified code: use it only when the record doesn't document anything more specific. If the record has more detail, check the other codes under A90-A99 below.
- As a secondary diagnosis it is a CC (complication or comorbidity), which can raise the MS-DRG payment. It doesn't count when the principal diagnosis is one of 23 closely related codes.
- Doesn't count toward a Medicare Advantage risk score (no HCC in V28).
- AHRQ's Chronic Condition Indicator classes it as not chronic (an acute or short-term condition).
Also indexed as: Fever, hemorrhagic NOS, viral
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Official coding guidelines
From the ICD-10-CM Official Guidelines for Coding and Reporting, FY 2027 (CMS and NCHS). Links open the PDF at the right page.
Rules for coding infections and parasitic diseases, including HIV, organism and drug resistance codes, sepsis and septic shock, MRSA, Zika, and COVID-19.
- Human Immunodeficiency Virus (HIV) Infections (page 19)
- Infectious agents as the cause of diseases classified to other chapters (page 22)
- Infections resistant to antibiotics (page 22)
- Sepsis, Severe Sepsis, and Septic Shock (page 23)
- Methicillin Resistant Staphylococcus aureus (MRSA) Conditions (page 27)
- Zika virus infections (page 28)
- Coronavirus infections (page 28)
Other codes under A90-A99
Arthropod-borne viral fevers and viral hemorrhagic fevers (A90-A99)
- A90Dengue fever [classical dengue]
- A91Dengue hemorrhagic fever
- A92Other mosquito-borne viral fevers
- A93Other arthropod-borne viral fevers, not elsewhere classified
- A94Unspecified arthropod-borne viral fever
- A95Yellow fever
- A96Arenaviral hemorrhagic fever
- A98Other viral hemorrhagic fevers, not elsewhere classified
- A99Unspecified viral hemorrhagic fever(this code)
A99 MS-DRGs
As the principal diagnosis, A99 groups to MS-DRG 865 or 866 (v44.0). Which one applies depends on procedures performed, secondary diagnoses (CC/MCC), and the patient's age and discharge status.
Related conditions
Grouped by AHRQ's Clinical Classifications Software Refined (CCSR), which sorts every diagnosis code into clinically meaningful categories.
A99 is in Viral infection (INF008, its default category), with 309 codes. Others in it:
About the condition
Plain-language background from MedlinePlus (National Library of Medicine), not coding guidance.
Hemorrhagic Fevers
Viral hemorrhagic fevers (VHFs) are a group of illnesses caused by four families of viruses. These include the Ebola and Marburg, Lassa fever, and yellow fever viruses. VHFs have common features: they affect many organs, they damage the blood vessels, and they affect the body's ability to regulate itself. Some VHFs cause mild disease, but some, like Ebola or Marburg, cause severe disease and death.
Read more about hemorrhagic fevers on MedlinePlusCode history
Valid since FY2016, when ICD-10-CM took effect on October 1, 2015. No changes since.
ICD-9-CM equivalent
Legacy crosswalk from the CMS General Equivalence Mappings (last updated 2018).
- 065.9 Arthropod-borne hemorrhagic fever, unspecified (approximate)