All ICD10 Codes
Chapter 1

A00–B99: Certain Infectious and Parasitic Diseases

Certain Infectious and Parasitic Diseases diagnostic classification updated for 2026.

Chapter Instructions

Includes
  • diseases generally recognized as communicable or transmissible
Excludes1(Not coded here. Use a different code.)
  • certain localized infections - see body system-related chapters
Excludes2(Not included here. Code separately if applicable.)
  • carrier or suspected carrier of infectious disease (Z22.-)
  • 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)
Use Additional Code
  • code to identify resistance to antimicrobial drugs (Z16.-)
All CodesBillable Only
Internal Codes
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  • A27—

    Leptospirosis

  • A27.0—

    Leptospirosis icterohemorrhagica

  • A27.8—

    Other forms of leptospirosis

  • A27.81—

    Aseptic meningitis in leptospirosis

  • A27.89—

    Other forms of leptospirosis

  • A27.9—

    Leptospirosis, unspecified

  • A28—

    Other zoonotic bacterial diseases, not elsewhere classified

  • A28.0—

    Pasteurellosis

  • A28.1—

    Cat-scratch disease

  • A28.2—

    Extraintestinal yersiniosis

  • A28.8—

    Other specified zoonotic bacterial diseases, not elsewhere classified

  • A28.9—

    Zoonotic bacterial disease, unspecified

  • A30—

    Leprosy [Hansen's disease]

  • A30.0—

    Indeterminate leprosy

  • A30.1—

    Tuberculoid leprosy

  • A30.2—

    Borderline tuberculoid leprosy

  • A30.3—

    Borderline leprosy

  • A30.4—

    Borderline lepromatous leprosy

  • A30.5—

    Lepromatous leprosy

  • A30.8—

    Other forms of leprosy

  • A30.9—

    Leprosy, unspecified

  • A31—

    Infection due to other mycobacteria

  • A31.0—

    Pulmonary mycobacterial infection

  • A31.1—

    Cutaneous mycobacterial infection

  • A31.2—

    Disseminated mycobacterium avium-intracellulare complex (DMAC)

  • A31.8—

    Other mycobacterial infections

  • A31.9—

    Mycobacterial infection, unspecified

  • A32—

    Listeriosis

  • A32.0—

    Cutaneous listeriosis

  • A32.1—

    Listerial meningitis and meningoencephalitis

  • A32.11—

    Listerial meningitis

  • A32.12—

    Listerial meningoencephalitis

  • A32.7—

    Listerial sepsis

  • A32.8—

    Other forms of listeriosis

  • A32.81—

    Oculoglandular listeriosis

  • A32.82—

    Listerial endocarditis

  • A32.89—

    Other forms of listeriosis

  • A32.9—

    Listeriosis, unspecified

  • A33—

    Tetanus neonatorum

  • A34—

    Obstetrical tetanus

  • A35—

    Other tetanus

  • A36—

    Diphtheria

  • A36.0—

    Pharyngeal diphtheria

  • A36.1—

    Nasopharyngeal diphtheria

  • A36.2—

    Laryngeal diphtheria

  • A36.3—

    Cutaneous diphtheria

  • A36.8—

    Other diphtheria

  • A36.81—

    Diphtheritic cardiomyopathy

  • A36.82—

    Diphtheritic radiculomyelitis

  • A36.83—

    Diphtheritic polyneuritis

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