B34 ICD-10-CM Code: Viral infection of unspecified site
B34 is not a CMS-HCC payment code. MEAT criteria · RAF Calculator · free HCC coding tools
HCC Buddy Code Card
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FY 2026 Apr update / Certain infectious and parasitic diseases (A00-B99) / Other viral diseases (B25-B34)
B34
Header CodeICD-10-CMOfficial ICD-10-CMCodebook guidanceViral infection of unspecified site
CMS-HCC V28
N/A—
Not mapped
CMS-HCC V24
N/A—
Not mapped
ACA/HHS
N/A—
Not mapped
ESRD/PACE
N/A—
Not mapped
RXHCC
N/A—
Not mapped
Code Book Path
Inclusion Terms
OfficialNo inclusion terms are included in this display for B34. Check the code and parent instructions in the Code Book.
Excludes 2
Official- carrier or suspected carrier of infectious disease (Z22.-)Inherited from A00-B99
- infectious and parasitic diseases complicating pregnancy, childbirth and the puerperium (O98.-)Inherited from A00-B99
- infectious and parasitic diseases specific to the perinatal period (P35-P39)Inherited from A00-B99
- influenza and other acute respiratory infections (J00-J22)Inherited from A00-B99
Related Codes
Includes
Official- diseases generally recognized as communicable or transmissibleInherited from A00-B99
Excludes 1
Official- anogenital human papillomavirus infection (A63.0)
- cytomegaloviral disease NOS (B25.9)
- herpesvirus [herpes simplex] infection NOS (B00.9)
- retrovirus infection NOS (B33.3)
- viral agents as the cause of diseases classified elsewhere (B97.-)
- viral warts due to human papillomavirus infection (B07)
- certain localized infections - see body system-related chaptersInherited from A00-B99
Code First
OfficialNo Code First sequencing instructions are included in this display for B34. Check the code and parent instructions in the Code Book.
Use Additional
Official- code to identify resistance to antimicrobial drugs (Z16.-)Inherited from A00-B99
Code Also
OfficialNo Code Also instructions are included in this display for B34. Check the code and parent instructions in the Code Book.
Current with CMS: FY2026 ICD-10-CM Apr 1 update (effective Apr 1 – Sep 30, 2026) · CMS-HCC V28, 100% phased in for payment year 2026. FY2027 code set already staged for October 1, 2026. How HCC Buddy stays current →
- Code
- B34
- Description
- Viral infection of unspecified site
- HCC (V28)
- No CMS-HCC V28 mapping
- RAF reference coefficient
- —
- Billable
- No
- Payment year
- 2026
Coder workflow notes
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What This Code Means
B34 is the ICD-10-CM diagnosis code for viral infection of unspecified site. B34 sits in the ICD-10-CM chapter for certain infectious and parasitic diseases (a00-b99), within the section covering other viral diseases (b25-b34).
Header codes like B34 cannot be reported on claims directly; they organize child codes that share clinical context. Coders should select the billable child code that matches the documented presentation and then verify its current source-backed HCC mapping. Do not infer a child code or risk adjustment value from the header alone.
HCC Buddy maintains structured V28 and V24 mapping, source-labeled coefficient references, and MEAT documentation criteria for B34 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.