A39.51 ICD-10-CM Code: Meningococcal endocarditis
HCC Buddy Code Card
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FY 2026 Apr update / Certain infectious and parasitic diseases (A00-B99) / Other bacterial diseases (A30-A49)
A39.51
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceMeningococcal endocarditis
This is a serious infection of the heart's inner lining (endocardium) caused by meningococcal bacteria. It's a life-threatening condition that requires immediate medical treatment with antibiotics.
CMS-HCC V28
00
RAF 0
CMS-HCC V24
00
RAF 0
ACA/HHS
00
RAF 0
ESRD/PACE
00
RAF 0
RXHCC
00
RAF 0
Code Trumping
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Code Book Path
Inclusion Terms
OfficialICD-10-CM does not list inclusion terms for A39.51 in this effective period.
Excludes 2
OfficialICD-10-CM does not list Excludes 2 notes for A39.51 in this effective period.
Related Child Codes
Includes
OfficialICD-10-CM does not list Includes notes for A39.51 in this effective period.
Excludes 1
OfficialICD-10-CM does not list Excludes 1 notes for A39.51 in this effective period.
Code First
OfficialICD-10-CM does not list Code First sequencing instructions for A39.51 in this effective period.
Use Additional
OfficialICD-10-CM does not list Use Additional Code instructions for A39.51 in this effective period.
Code Also
OfficialICD-10-CM does not list Code Also instructions for A39.51 in this effective period.
Buddy Documentation Tip
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 A39.51 an HCC code?
No. A39.51 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
A39.51 is the ICD-10-CM diagnosis code for meningococcal endocarditis. This is a serious infection of the heart's inner lining (endocardium) caused by meningococcal bacteria. It's a life-threatening condition that requires immediate medical treatment with antibiotics. A39.51 sits in the ICD-10-CM chapter for certain infectious and parasitic diseases (a00-b99), within the section covering other bacterial diseases (a30-a49).
A39.51 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 that the endocarditis is specifically documented as meningococcal in origin; do not assume meningococcal infection without explicit documentation.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for A39.51 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Verify that the endocarditis is specifically documented as meningococcal in origin; do not assume meningococcal infection without explicit documentation
- •This code should be used in conjunction with codes identifying the specific valve(s) affected if documented (e.g., aortic, mitral, tricuspid, or pulmonary valve involvement)