Other viral diseases, not elsewhere classified (B33) ICD-10-CM
The B33 code range covers other viral diseases, not elsewhere classified with 12 ICD-10-CM diagnosis codes. 10 of them are billable and valid for claim submission in fiscal year 2026, and the category headers group them but cannot themselves be billed.
Codes in the B33 Range 12 codes · 10 billable
- B33 Other viral diseases, not elsewhere classifiedNon-billable
- B33.0 Epidemic myalgia
- B33.1 Ross River disease
- B33.2 Viral carditisNon-billable
- B33.20 Viral carditis, unspecified
- B33.21 Viral endocarditis
- B33.22 Viral myocarditis
- B33.23 Viral pericarditis
- B33.24 Viral cardiomyopathy
- B33.3 Retrovirus infections, not elsewhere classified
- B33.4 Hantavirus (cardio)-pulmonary syndrome [HPS] [HCPS]
- B33.8 Other specified viral diseases
Clinical Terms in This Code Range
Definitions from the National Library of Medicine for conditions coded in the B33 range.
Hantavirus Pulmonary Syndrome
Acute respiratory illness in humans caused by the SIN NOMBRE VIRUS whose primary rodent reservoir is the deer mouse Peromyscus maniculatus. First identified in the southwestern United States, this syndrome is characterized most commonly by fever, myalgias, headache, cough, and rapid respiratory failure.
Sin Nombre virus
A species of ORTHOHANTAVIRUS which emerged in the Four Corners area of the United States in 1993. It causes a serious, often fatal pulmonary illness (HANTAVIRUS PULMONARY SYNDROME) in humans. Transmission is by inhaling aerosolized rodent secretions that contain virus particles, carried especially by deer mice (PEROMYSCUS maniculatus) and pinyon mice (P. truei).
About the B33 Code Range
The ICD-10 code section B33 covers various other viral diseases not classified elsewhere. It includes specific conditions caused by different viruses, such as epidemic myalgia, viral carditis, and retrovirus infections.
This section helps medical coders identify and report viral infections that do not fit into other predefined categories. For example, B33.0 is used for epidemic myalgia, also known as viral myalgia or epidemic pleurodynia, which involves muscle pain linked to viral infections. Codes B33.20 through B33.24 categorize viral carditis, encompassing myocarditis, endocarditis, pericarditis, and cardiomyopathy caused by viruses like Coxsackie or enteroviruses. The code B33.3 identifies infections from retroviruses, while B33.4 covers hantavirus pulmonary syndrome, a serious cardiopulmonary condition. Additionally, B33.8 includes a diverse group of other specified viral diseases caused by rare or less common viruses. Knowing the ICD-10 code for epidemic myalgia or viral myocarditis can aid healthcare professionals and coders in precise documentation and billing for these unique viral illnesses.
Questions About This Page
How many billable codes are in the B33 range?
Of the 12 codes in this range, 10 are billable and valid for claim submission from October 1, 2025 through September 30, 2026. Category header codes group them but cannot be reported on claims.
What does the B33 range classify?
The range classifies other viral diseases, not elsewhere classified. Each code links to its own reference page with billing status, MS-DRG grouping, coding notes, and clinical information.
Related References
Source: CMS FY 2026 ICD-10-CM Tabular List and order file, effective October 1, 2025 through September 30, 2026.
