A30-A49
Medium Complexity

Other bacterial diseases

Primary Specialty: Infectious Disease
Last Updated: 2025-09-09

ICD-10 Codes (135)

132 billable
3 category headers
A31
Infection due to other mycobacteria
View
A31.0
Billable
Pulmonary mycobacterial infection
View
A31.1
Billable
Pulmonary mycobacterial infection
View
A31.2
Billable
Disseminated mycobacterium avium-intracellulare complex (MAC) infection
View
A31.8
Billable
Other mycobacterial diseases of other organs
View
A31.9
Billable
Granulomatous disease, unspecified.
View
A32
Tularemia
View
A32.0
Billable
Lassa fever
View
A32.1
Billable
Listeriosis
View
A32.11
Billable
Listerial meningitis
View
A32.12
Billable
Listerial meningoencephalitis
View
A32.7
Billable
Lassa fever
View
A32.8
Billable
Other forms of listeriosis
View
A32.81
Billable
Oculoglandular listeriosis
View
A32.82
Billable
Listerial endocarditis
View
A32.89
Billable
Other forms of listeriosis
View
A32.9
Billable
Tularemia, unspecified
View
A33
Billable
Tetanus neonatorum
View
A34
Billable
Obstetrical tetanus
View
A35
Billable
Other specified bacterial diseases
View
A36
Billable
Diphtheria
View
A36.0
Billable
Meningococcal meningitis, group A
View
A36.1
Billable
Erysipeloid
View
A36.2
Billable
Meningococcal meningitis, unspecified
View
A36.3
Billable
Meningococcal endocarditis
View
A36.8
Billable
Other specified tetanus
View
A36.81
Billable
Diphtheritic cardiomyopathy
View
A36.82
Billable
Diphtheritic radiculomyelitis
View
A36.83
Billable
Diphtheritic polyneuritis
View
A36.84
Billable
Diphtheritic tubulo-interstitial nephropathy
View
A36.85
Billable
Diphtheritic cystitis
View
A36.86
Billable
Diphtheritic conjunctivitis
View
A36.89
Billable
Other diphtheritic complications
View
A36.9
Billable
Meningococcal meningitis, unspecified
View
A37
Billable
Whooping cough due to Bordetella pertussis
View
A37.0
Billable
Whooping cough due to Bordetella pertussis
View
A37.00
Billable
Whooping cough due to Bordetella pertussis without pneumonia
View
A37.01
Billable
Whooping cough due to Bordetella pertussis with pneumonia
View
A37.1
Billable
Whooping cough due to Bordetella pertussis
View
A37.10
Billable
Whooping cough due to Bordetella parapertussis without pneumonia
View
A37.11
Billable
Whooping cough due to Bordetella parapertussis with pneumonia
View
A37.8
Billable
Whooping cough due to other Bordetella species
View
A37.80
Billable
Whooping cough due to other Bordetella species without pneumonia
View
A37.81
Billable
Whooping cough due to other Bordetella species with pneumonia
View
A37.9
Billable
Whooping cough, unspecified
View
A37.90
Billable
Whooping cough, unspecified species without pneumonia
View
A37.91
Billable
Whooping cough, unspecified species with pneumonia
View
A38
Billable
Scarlet fever
View
A38.0
Billable
Scarlet fever
View
A38.1
Billable
Scarlet fever
View
A38.8
Billable
Other forms of tetanus
View
A38.9
Billable
Scarlet fever, unspecified
View
A39
Billable
Meningococcal infection
View
A39.0
Billable
Meningococcal meningitis
View
A39.1
Billable
Meningococcal meningitis, unspecified
View
A39.2
Billable
Meningococcal meningitis, unspecified
View
A39.3
Billable
Meningococcal septicemia, unspecified
View
A39.4
Billable
Meningococcal meningitis, unspecified
View
A39.5
Billable
Meningococcal meningitis, unspecified
View
A39.50
Billable
Meningococcal carditis, unspecified
View
A39.51
Billable
Meningococcal endocarditis
View
A39.52
Billable
Meningococcal myocarditis
View
A39.53
Billable
Meningococcal pericarditis
View
A39.8
Billable
Other specified meningococcal infections
View
A39.81
Billable
Meningococcal encephalitis
View
A39.82
Billable
Meningococcal retrobulbar neuritis
View
A39.83
Billable
Meningococcal arthritis
View
A39.84
Billable
Postmeningococcal arthritis
View
A39.89
Billable
Other meningococcal infections
View
A39.9
Billable
Meningococcal infection, unspecified
View
A40
Billable
Streptococcal sepsis.
View
A40.0
Billable
Sepsis due to streptococcus, group A
View
A40.1
Billable
Sepsis due to streptococcus, group B
View
A40.3
Billable
Sepsis due to streptococcus, group B
View
A40.8
Billable
Other specified streptococcal sepsis
View
A40.9
Billable
Sepsis, unspecified organism
View
A41
Billable
Septicemia
View
A41.0
Billable
Sepsis due to Staphylococcus aureus
View
A41.01
Billable
Sepsis due to Methicillin susceptible Staphylococcus aureus
View
A41.02
Billable
Sepsis due to Methicillin resistant Staphylococcus aureus
View
A41.1
Billable
Sepsis due to other specified staphylococcus.
View
A41.2
Billable
Sepsis due to other specified staphylococcus.
View
A41.3
Billable
Sepsis due to other specified staphylococcus.
View
A41.4
Billable
Sepsis due to other Gram-negative organisms
View
A41.5
Billable
Sepsis due to other Gram-negative organisms
View
A41.50
Billable
Gram-negative sepsis, unspecified
View
A41.51
Billable
Sepsis due to Escherichia coli [E. coli]
View
A41.52
Billable
Sepsis due to Pseudomonas
View
A41.53
Billable
Sepsis due to Serratia
View
A41.54
Billable
Sepsis due to Acinetobacter baumannii
View
A41.59
Billable
Other Gram-negative sepsis
View
A41.8
Billable
Other specified sepsis
View
A41.81
Billable
Sepsis due to Enterococcus
View
A41.89
Billable
Other specified sepsis
View
A41.9
Billable
Sepsis, unspecified organism
View
A42
Billable
Actinomycosis
View
A42.0
Billable
Actinomycotic brain abscess
View
A42.1
Billable
Actinomycotic sepsis
View
A42.2
Billable
Actinomycotic brain abscess
View
A42.7
Billable
Actinomycotic sepsis
View
A42.8
Billable
Other forms of actinomycosis
View
A42.81
Billable
Actinomycotic meningitis
View
A42.82
Billable
Actinomycotic encephalitis
View
A42.89
Billable
Other forms of actinomycosis
View
A42.9
Billable
Actinomycosis, unspecified
View
A43
Billable
Scarlet fever
View
A43.0
Billable
Whooping cough due to Bordetella pertussis
View
A43.1
Billable
Sepsis due to anaerobes
View
A43.8
Billable
Other forms of endocarditis
View
A43.9
Billable
Scarlet fever, unspecified
View
A44
Billable
Invasive meningococcal disease
View
A44.0
Billable
Invasive meningococcal disease
View
A44.1
Billable
Pulmonary actinomycosis
View
A44.8
Billable
Other specified bartonellosis
View
A44.9
Billable
Invasive meningococcal disease, unspecified
View
A46
Billable
Erysipelas
View
A48
Billable
Other bacterial diseases, not elsewhere classified
View
A48.0
Billable
Gas gangrene
View
A48.1
Billable
Legionnaires' disease
View
A48.2
Billable
Toxic shock syndrome
View
A48.3
Billable
Toxic shock syndrome
View
A48.4
Billable
Bartonellosis
View
A48.5
Billable
Legionnaires' disease
View
A48.51
Billable
Infant botulism
View
A48.52
Billable
Wound botulism
View
A48.8
Billable
Other specified bacterial diseases
View
A49
Bacterial infection, unspecified site
View
A49.0
Billable
Streptococcal sore throat
View
A49.01
Billable
Methicillin susceptible Staphylococcus aureus infection, unspecified site
View
A49.02
Billable
Methicillin resistant Staphylococcus aureus infection, unspecified site
View
A49.1
Billable
Legionnaires' disease
View
A49.2
Billable
Bacterial infection of unspecified site, unspecified.
View
A49.3
Billable
Acute bacterial prostatitis
View
A49.8
Billable
Other bacterial diseases, not elsewhere classified
View
A49.9
Billable
Bacterial infection, unspecified
View

Updates & Changes

FY 2026 Updates

Current Year

New Codes (2)

A04.72
Enterocolitis due to Clostridioides difficile, recurrent
A04.73
Enterocolitis due to Clostridioides difficile, not responsive to therapy

Revised Codes (2)

A04.71
Updated to clarify "initial episode" terminology for Clostridioides difficile
A08.11
Acute gastroenteropathy due to Norovirus - enhanced specificity

Deleted Codes

No codes deleted in this range for FY 2026

Historical Changes

  • FY 2025: Routine maintenance updates with minor terminology clarifications
  • FY 2024: Enhanced specificity requirements for certain code ranges
  • FY 2023: Updated documentation guidelines for improved clarity

Upcoming Changes

  • Proposed updates pending review by Coordination and Maintenance Committee
  • Under consideration: Enhanced digital health integration codes

Implementation Guidance

  • Review all FY 2026 updates for A30-A49 codes before implementation
  • Always verify the most current codes in the ICD-10-CM manual
  • Ensure clinical documentation supports the selected diagnosis codes
  • +3 more guidance items...

Range Overview

high priority

The ICD-10 code range A30-A49 pertains to 'Other bacterial diseases'. These codes are used to classify and document various bacterial infections not classified elsewhere. The range includes diseases like leprosy, diphtheria, whooping cough, and other nonvenereal treponemal infections. These codes are essential for accurate medical documentation and statistical analysis of disease prevalence.

Key Usage Points:

  • A30-A49 codes are used for bacterial diseases not classified elsewhere.
  • The codes are specific to the type of bacterial infection.
  • Codes can be used to track disease prevalence and treatment outcomes.
  • Accurate coding is essential for appropriate billing and reimbursement.
  • Some codes within this range may require additional codes to fully describe the condition.

Coding Guidelines

When to Use:

  • When a patient is diagnosed with a bacterial disease not classified elsewhere.
  • When a bacterial disease is the primary reason for a patient's visit.
  • When a bacterial disease is a comorbidity that affects patient care.
  • When documenting the history of a bacterial disease.

When NOT to Use:

  • When the bacterial disease is classified elsewhere.
  • When the patient is only at risk of the disease, without a confirmed diagnosis.
  • When the patient has a viral, fungal, or other non-bacterial infection.
  • When the bacterial disease is an incidental finding.

Code Exclusions

Always verify exclusions by cross-referencing the ICD-10 manual and any updates.

Documentation Requirements

Accurate documentation is crucial for correct coding. It should include the specific bacterial disease, its severity, any complications, and the patient's response to treatment.

Clinical Information:

  • Specific bacterial disease diagnosis
  • Severity of the disease
  • Any related complications
  • Response to treatment

Supporting Evidence:

  • Lab results confirming the bacterial infection
  • Clinical notes detailing the patient's symptoms and treatment plan
  • Imaging or other diagnostic test results if applicable
Good Documentation Example:

Patient diagnosed with diphtheria, severe, with myocarditis. Confirmed by throat culture. Responding well to antibiotics.

Poor Documentation Example:

Patient has a bacterial infection.

Common Documentation Errors:

  • Not specifying the type of bacterial disease
  • Failing to document the severity of the disease
  • Not noting any related complications
  • Not including supporting evidence

Range Statistics

Total Codes
132
Billable
Complexity:
Medium
Primary Use:Clinical Documentation
Chapter:1

Coding Complexity

Medium
Complexity Rating

The complexity of A30-A49 coding is considered medium due to the need for specificity in identifying the bacterial disease, understanding of disease severity, potential for complications requiring additional codes, and knowledge of code exclusions.

Key Factors:
  • Need to identify the specific bacterial disease
  • Requirement for additional codes for complications
  • Understanding of disease severity
  • Knowledge of code exclusions

Specialty Focus

These codes are most commonly used in infectious disease, internal medicine, and family practice specialties, but can be relevant in any setting where bacterial diseases are diagnosed.

Primary Specialties:
Infectious Disease
40%
Internal Medicine
30%
Family Practice
20%
Clinical Scenarios:
  • A patient presenting with a severe cough and confirmed whooping cough diagnosis.
  • A patient with a history of leprosy requiring ongoing management.
  • A patient with diphtheria and related myocarditis.
  • A patient with a nonvenereal treponemal infection.

Resources & References

Resources for A30-A49 include the ICD-10 manual, official coding guidelines, and clinical reference materials.

Official Guidelines:

  • ICD-10-CM Official Guidelines for Coding and Reporting
  • American Health Information Management Association (AHIMA) guidelines
  • Centers for Disease Control and Prevention (CDC) guidelines

Clinical References:

  • UpToDate
  • Medscape

Educational Materials:

  • AHIMA ICD-10 training materials
  • CDC ICD-10 educational resources

Frequently Asked Questions

Can A30-A49 codes be used for suspected bacterial diseases?

No, these codes should only be used for confirmed diagnoses. For suspected conditions, use the appropriate code from the R00-R99 range for symptoms, signs, and abnormal clinical and laboratory findings.