B99 Other and unspecified infectious diseases

The ICD-10-CM code for Other and unspecified infectious diseases is B99 (FY2026). It is a non-billable category code — select a more specific code below for claims.

Classification

Chapter

1: Certain infectious and parasitic diseases (A00-B99)

Section

B99: Other infectious diseases (B99)

Category B99

3 codes (2 billable)

FY2026 Status

Stable since FY2024

Also Known As

ICD-10-CM Alphabetic Index entries that lead to B99:

• Pneumonia (acute) (double) (migratory) (purulent) (septic) (unresolved) › postinfectional NEC
• Arthropathy › postinfectious NEC
• Myopathy › in (due to) › infectious disease NEC
• Encephalitis (chronic) (hemorrhagic) (idiopathic) (nonepidemic) (spurious) (subacute) › in (due to) › infectious disease NEC
• Conjunctivitis (staphylococcal) (streptococcal) NOS › in (due to) › infectious disease NEC
• Iridocyclitis › in (due to) › infectious disease NOS
• Mastoiditis (coalescent) (hemorrhagic) (suppurative) › in (due to) › infectious disease NEC
• Neuritis (rheumatoid) › acoustic (nerve) › in (due to) › infectious disease NEC

Official Coding Guidelines

Chapter 1 TOC entry

1. Chapter 1: Certain Infectious and Parasitic Diseases (A00-B99), U07.1, U09.9 ................... 19

HIV Infections (TOC entry)

a. Human Immunodeficiency Virus (HIV) Infections .............................................................. 19

Source: CMS — ICD-10-CM Official Guidelines for Coding and Reporting, FY2026

References

• CMS — ICD-10-CM Official Code Set and Guidelines, FY2026
• CDC/NCHS — ICD-10-CM Files and Browser Tool