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A49 ICD-10-CM Code: Bacterial infection of unspecified site

ICD-10-CM Code View

HCC Buddy Code Card

Digital ICD-10 code-book layout with official code detail, always-visible risk models, Code Trumping, and Buddy coding guidance.

FY 2026 Apr update / Certain infectious and parasitic diseases (A00-B99) / Other bacterial diseases (A30-A49)

A49

Header CodeICD-10-CMOfficial ICD-10-CMCodebook guidance

Bacterial infection of unspecified site

Bacterial infection of unspecified site

CMS-HCC V28

N/A

Not mapped

CMS-HCC V24

N/A

Not mapped

ACA/HHS

N/A

Not mapped

ESRD/PACE

N/A

Not mapped

RXHCC

N/A

Not mapped

Code Book Path

Official
A4Other bacterial diseases (A30-A49)
A49Bacterial infection of unspecified site

Inclusion Terms

Official

ICD-10-CM does not list inclusion terms for A49 in this effective period.

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for A49 in this effective period.

Related Child Codes

Official
A49.0Staphylococcal infection, unspecified site
A49.1Streptococcal infection, unspecified site
A49.2Hemophilus influenzae infection, unspecified site
A49.3Mycoplasma infection, unspecified site
A49.8Other bacterial infections of unspecified site

Includes

Official

ICD-10-CM does not list Includes notes for A49 in this effective period.

Excludes 1

Official
  • 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)

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for A49 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for A49 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for A49 in this effective period.

Last updated: FY2026 ICD-10-CM Apr update, Apr 1, 2026 through Sep 30, 2026. CMS-HCC V28 is 100% phased in for payment year 2026.

Coder workflow notes

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What This Code Means

A49 is the ICD-10-CM diagnosis code for bacterial infection of unspecified site. A49 sits in the ICD-10-CM chapter for certain infectious and parasitic diseases (a00-b99), within the section covering other bacterial diseases (a30-a49).

Header codes like A49 cannot be reported on claims directly, they organize child codes that share clinical context but the actual diagnosis must be coded to the highest level of specificity supported by the documentation. Coders should look at A49's child codes and select the one that matches the patient's documented presentation, since payers reject header codes submitted as the primary diagnosis. For risk adjustment workflows, header codes never contribute to a Medicare Advantage member's RAF score on their own; only billable child codes that happen to map to a payment HCC affect risk-adjusted plan payments.

HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for A49 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Excludes 1, 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)

Child Codes

Code Hierarchy

A49Bacterial infection of unspecified site
A49Bacterial infection of unspecified site

Work A49 in HCC Buddy

Open A49 in the Code Book for the full Index-to-Tabular path, MEAT checklist, and V28 HCC mapping, or in the Encoder to code from a keyword search. Pro includes 14 days to try everything.