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A23.0 ICD-10-CM Code: Brucellosis due to Brucella melitensis

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FY 2026 Apr update / Certain infectious and parasitic diseases (A00-B99) / Certain zoonotic bacterial diseases (A20-A28)

A23.0

Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidance

Brucellosis due to Brucella melitensis

This is a bacterial infection caused by Brucella melitensis, typically acquired from contact with infected animals or contaminated animal products like unpasteurized milk and cheese. It causes fever, joint pain, and fatigue that can become chronic if untreated.

CMS-HCC V28

0

0

RAF 0

CMS-HCC V24

0

0

RAF 0

ACA/HHS

0

0

RAF 0

ESRD/PACE

0

0

RAF 0

RXHCC

0

0

RAF 0

Code Trumping

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Code Book Path

Official
A23Brucellosis
A23.0Brucellosis due to Brucella melitensis

Inclusion Terms

Official

ICD-10-CM does not list inclusion terms for A23.0 in this effective period.

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for A23.0 in this effective period.

Related Child Codes

Official
A23.1Brucellosis due to Brucella abortus
A23.2Brucellosis due to Brucella suis
A23.3Brucellosis due to Brucella canis
A23.8Other brucellosis
A23.9Brucellosis, unspecified

Includes

Official
  • Malta fever
  • Mediterranean fever
  • undulant fever

Excludes 1

Official

ICD-10-CM does not list Excludes 1 notes for A23.0 in this effective period.

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for A23.0 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for A23.0 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for A23.0 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance
Verify the specific Brucella species (melitensis, abortus, suis, or canis) is documented before assigning this code, as each has a different code
Document the source of infection when possible (occupational exposure, food consumption, animal contact) as this may support medical necessity and help with public health reporting

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.

Is A23.0 an HCC code?

No. A23.0 is a billable ICD-10-CM code but does not map to any HCC category in V28, V24, ESRD, or RxHCC.

Coder workflow notes

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This code does not map to an HCC category in any model (V28, V24, ESRD, RxHCC).

What This Code Means

A23.0 is the ICD-10-CM diagnosis code for brucellosis due to brucella melitensis. This is a bacterial infection caused by Brucella melitensis, typically acquired from contact with infected animals or contaminated animal products like unpasteurized milk and cheese. It causes fever, joint pain, and fatigue that can become chronic if untreated. A23.0 sits in the ICD-10-CM chapter for certain infectious and parasitic diseases (a00-b99), within the section covering certain zoonotic bacterial diseases (a20-a28).

A23.0 is a billable ICD-10-CM code but does not map to a payment HCC under the CMS-HCC V28, V24, ESRD, or RxHCC risk adjustment models. It can be reported on Medicare Advantage encounter data submissions but it does not contribute to a beneficiary's RAF score and therefore does not affect risk-adjusted payments to the plan.

Verify the specific Brucella species (melitensis, abortus, suis, or canis) is documented before assigning this code, as each has a different code.

HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for A23.0 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

  • Verify the specific Brucella species (melitensis, abortus, suis, or canis) is documented before assigning this code, as each has a different code
  • Document the source of infection when possible (occupational exposure, food consumption, animal contact) as this may support medical necessity and help with public health reporting

Child Codes

Code Hierarchy

A23BrucellosisA23.0Brucellosis due to Brucella melitensis
A23.0Brucellosis due to Brucella melitensis

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