HealthAssure
HealthAssureGood Life
ICD10

ICD-10 Code A49: Bacterial infection of unspecified site

A49 is an ICD-10 diagnosis entry used to group records related to Bacterial infection of unspecified site. You may see this entry in coding references, medical records, or claims workflows when a broader diagnosis category is being reviewed before a more specific code is chosen. ICD-10 entries help standardize how diagnoses are organized for coding, reporting, analytics, and documentation. This code sits within the broader ICD-10 area for Certain infectious and parasitic diseases (A00-B99).

What is this code?

ICD-10 entries help standardize how diagnoses are organized for coding, reporting, analytics, and documentation. This code sits within the broader ICD-10 area for Certain infectious and parasitic diseases (A00-B99).

đź“‹Clinical overview

This ICD-10 code is commonly used when documentation describes a bacterial infection without a clearly documented body site. The most accurate code depends on whether the chart identifies staphylococcal, streptococcal, Hemophilus influenzae, mycoplasma, other bacterial, or fully unspecified infection, and whether resistance detail such as MRSA versus MSSA is documented.

When is it used?

  • May be used when a clinician documents bacterial infection of unspecified site in a patient's medical record.
  • May appear in hospital records, claims, referrals, and clinical documentation.
  • This code may act more like a grouping or parent code, so a more specific child code may be used in final documentation when available.

What it does not mean

  • A code alone does not explain severity, treatment plan, or outcome.
  • A medical code should not be treated as a substitute for a doctor's diagnosis or advice.
  • This entry may represent a broader category rather than the most specific billable code.

đź©şClinical context

When commonly used
  • Primary-care, urgent-care, emergency, inpatient, infectious-disease, and follow-up documentation where bacterial infection is part of the active assessment but the affected body site is not yet clearly documented on the page being reviewed.
  • Coding and utilization-review workflows where organism detail or resistance detail changes final code specificity even before a more precise anatomic site is named elsewhere in the record.
Common management context
  • Evaluation often includes symptom review, culture or molecular-test review, CBC or inflammatory-marker context, antibiotic-selection planning, and follow-up to clarify organism identity, resistance pattern, and the likely infectious source.
  • Documentation usually becomes more specific when the chart identifies the organism more narrowly, distinguishes MRSA from MSSA, or names the affected body site rather than leaving it unspecified.
  • Specialist context already linked on this page includes Infectious Disease Specialist, General Physician.

🔍Key distinctions

Important notes
  • This ICD-10 family captures bacterial infections that remain unspecified by body site on the page, and it is distinct from more specific site-based infection coding because organism and resistance detail are doing most of the specificity work here.
  • Named-organism detail matters across this branch, and MRSA-versus-MSSA detail is an additional specificity driver inside the staphylococcal subset.
  • This parent page groups bacterial-infection diagnoses where the organism may be named but the involved body site is still unspecified, so the final billable code usually depends on whether the chart identifies staphylococcal, streptococcal, Hemophilus influenzae, mycoplasma, other bacterial, or fully unspecified infection.
  • Documentation that describes bacterial infection is coded differently from viral, fungal, parasitic, or site-defined infectious conditions because organism and anatomic-site detail drive final code selection.
Important exclusions
  • bacterial agents as the cause of diseases classified elsewhere (B95-B96)
  • chlamydial infection NOS (A74.9)
  • meningococcal infection NOS (A39.9)
  • rickettsial infection NOS (A79.9)
  • spirochetal infection NOS (A69.9)
Related codes to consider
A49.1Streptococcal infection, unspecified site
Related bacterial-infection ICD-10 code; documentation often becomes more specific when the chart identifies the organism, distinguishes MRSA from MSSA, or names the affected body site.
A49.2Hemophilus influenzae infection, unspecified site
Related bacterial-infection ICD-10 code; documentation often becomes more specific when the chart identifies the organism, distinguishes MRSA from MSSA, or names the affected body site.
A49.3Mycoplasma infection, unspecified site
Related bacterial-infection ICD-10 code; documentation often becomes more specific when the chart identifies the organism, distinguishes MRSA from MSSA, or names the affected body site.
A49.8Other bacterial infections of unspecified site
Related bacterial-infection ICD-10 code; documentation often becomes more specific when the chart identifies the organism, distinguishes MRSA from MSSA, or names the affected body site.

Code hierarchy

chapter
1Certain infectious and parasitic diseases (A00-B99)
block
A30-A49Other bacterial diseases
currentA30-A49

Official coding notes

Excludes1 (do not code together)
  • bacterial agents as the cause of diseases classified elsewhere (B95-B96)
  • chlamydial infection NOS (A74.9)
  • meningococcal infection NOS (A39.9)
  • rickettsial infection NOS (A79.9)
  • spirochetal infection NOS (A69.9)

Where you may see this code

You may see this entry in coding references, medical records, or claims workflows when a broader diagnosis category is being reviewed before a more specific code is chosen.

Related specialists

Infectious Disease SpecialistGeneral Physician

Coding guidelines

Compatibility

Legacy code aligns to an official FY 2026 category. Frontend should resolve to the official category page and surface the billable child codes.
Legacy codes
A49
Replacement codes
A49.1 — Streptococcal infection, unspecified siteA49.2 — Hemophilus influenzae infection, unspecified siteA49.3 — Mycoplasma infection, unspecified siteA49.8 — Other bacterial infections of unspecified siteA49.9 — Bacterial infection, unspecified

Common synonyms

Bacterial infection of unspecified siteBacterial infection of site

Frequently asked questions

Code details

CodeA49
SystemICD10
Display nameBacterial infection of unspecified site
ChapterCertain infectious and parasitic diseases (A00-B99)
BlockOther bacterial diseases

Flags

BillableNo
Valid clinical useNo

Source

SourceICD-10
Version2026-annual
Releaseannual
Year2026

About this content

This page is prepared by HealthAssure's clinical team using official coding standards from ICD-10. AI tools assist with drafting explanations, which are then reviewed and verified by healthcare professionals for accuracy. This content is for informational purposes and does not replace professional medical advice. Meet our team.