Alphabetic Index FY2027

B99

Other and unspecified infectious diseases

FY2027Chapter 1: Certain infectious and parasitic diseases/B99 Other infectious diseases

Non-billable headerNot valid on its own. Use one of the more specific codes under it.

B99 is a non-billable ICD-10-CM code category for other and unspecified infectious diseases. Report a more specific code from it instead. It is part of the FY2027 code set, effective October 1, 2026. The more specific codes under it are B99.8 Other infectious disease and B99.9 Unspecified infectious disease. Its coding notes include a Use additional code instruction and 5 Excludes2 entries.

Use additional code

Add the listed code as a secondary code, if known.

Also from chapter/block level (1 note)
Inherited from Chapter 1 Certain infectious and parasitic diseases
  • code to identify resistance to antimicrobial drugs (Z16.-)

Excludes2

Not included here. Both codes may be reported if the patient has both conditions.

Also from chapter/block level (5 notes)
Inherited from Chapter 1 Certain infectious and parasitic diseases
  • 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)

Includes

Further defines or gives examples of the content of the category.

Also from chapter/block level (1 note)
Inherited from Chapter 1 Certain infectious and parasitic diseases
  • diseases generally recognized as communicable or transmissible

Alphabetic Index terms

Terms the official Alphabetic Index lists for this code. 11 entries

More specific codes under B99 2