B99

Other and unspecified infectious diseases

Not billable — category only FY2026 2025-10-01 → 2026-09-30

Exclusions 5 never code together

A00-B99chapter

Excludes1

certain localized infections - see body system-related chapters

Excludes2

carrier or suspected carrier of infectious disease (Z22.-)Z22.-
infectious and parasitic diseases complicating pregnancy, childbirth and the puerperium (O98.-)O98.-
infectious and parasitic diseases specific to the perinatal period (P35-P39)P35-P39
influenza and other acute respiratory infections (J00-J22)J00-J22

Excludes1 — never code together. The excluded condition and this one are mutually exclusive.

Excludes2 — not included here, but the patient may have both. Code both when documented.

Instructional notes 2

A00-B99chapter

Includes

diseases generally recognized as communicable or transmissible

Use additional code

code to identify resistance to antimicrobial drugs (Z16.-)Z16.-

Index entries leading here 11

Neuritis (rheumatoid) M79.2
- acoustic (nerve) H93.3
  - in (due to)
    - infectious disease NEC B99
Arthropathy M12.9
- postinfectious NEC B99
Conjunctivitis (staphylococcal) (streptococcal) NOS H10.9
- in (due to)
  - infectious disease NEC B99
Palsy G83.9
- cranial nerve — see also Disorder, nerve, cranial
  - multiple G52.7
    - in
      - infectious disease B99
Polyneuropathy (peripheral) G62.9
- in (due to)
  - infectious
    - disease NEC B99
Encephalitis (chronic) (hemorrhagic) (idiopathic) (nonepidemic) (spurious) (subacute) G04.90
- in (due to)
  - infectious disease NEC B99
Otitis (acute) H66.90
- externa H60.9
  - in (due to)
    - infectious disease NEC B99
Myopathy G72.9
- in (due to)
  - infectious disease NEC B99
Mastoiditis (coalescent) (hemorrhagic) (suppurative) H70.9
- in (due to)
  - infectious disease NEC B99
Iridocyclitis H20.9
- in (due to)
  - infectious disease NOS B99
Pneumonia (acute) (double) (migratory) (purulent) (septic) (unresolved) J18.9
- postinfectional NEC B99

Subordinate codes 2

B99.8 Other infectious disease B99.9 Unspecified infectious disease

Medications 1

55 Bone Diseases, Infectious drugs

MED-RT files conditions by MeSH, which carves the world differently from ICD-10. These are name matches on this code's description, offered as candidates — not as an assertion that they are this code.

Additional references

AHA Coding Clinic® Licence required

Official coding advice for this code. Published by the American Hospital Association. Not included in this installation.

Risk adjustment

Maps to no condition category in any loaded model.

Presence is a property of the code. Untick a model to hide it everywhere.

This code

Billable: no
Code set: FY2026
Subordinate: 2

Present FY2024–FY2027.