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I99.9 ICD-10-CM Code: Unspecified disorder of circulatory system

I99.9 is not a CMS-HCC payment code. MEAT criteria · RAF Calculator · free HCC coding tools

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Code lookupI99.9

FY 2026 Apr update / Diseases of the circulatory system (I00-I99) / Other and unspecified disorders of the circulatory system (I95-I99)

I99.9

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

Unspecified disorder of circulatory system

A heart or blood vessel disorder that is not specified or identified.

OverviewRisk ModelsCode BookDocumentationAuditNotesEdition comparison

CMS-HCC V28

N/A

—

Not mapped

CMS-HCC V24

Historical

Historical

Not used for CY2026 payment

ACA/HHS

N/A

—

Not mapped

ESRD/PACE

N/A

—

Not mapped

RXHCC

N/A

—

Not mapped

Code Book Path

Official
I99Other and unspecified disorders of circulatory systemI99.9Unspecified disorder of circulatory system

Inclusion Terms

Official

No inclusion terms are included in this display for I99.9. Check the code and parent instructions in the Code Book.

Excludes 2

Official
  • certain conditions originating in the perinatal period (P04-P96)Inherited from I00-I99
  • certain infectious and parasitic diseases (A00-B99)Inherited from I00-I99
  • complications of pregnancy, childbirth and the puerperium (O00-O9A)Inherited from I00-I99
  • congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)Inherited from I00-I99
  • endocrine, nutritional and metabolic diseases (E00-E88)Inherited from I00-I99
  • injury, poisoning and certain other consequences of external causes (S00-T88)Inherited from I00-I99
  • neoplasms (C00-D49)Inherited from I00-I99
  • symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)Inherited from I00-I99
  • systemic connective tissue disorders (M30-M36)Inherited from I00-I99
  • transient cerebral ischemic attacks and related syndromes (G45.-)Inherited from I00-I99

Related Codes

Official
I99.8Other disorder of circulatory system

Includes

Official

No Includes notes are included in this display for I99.9. Check the code and parent instructions in the Code Book.

Excludes 1

Official

No Excludes 1 notes are included in this display for I99.9. Check the code and parent instructions in the Code Book.

Code First

Official

No Code First sequencing instructions are included in this display for I99.9. Check the code and parent instructions in the Code Book.

Use Additional

Official

No Use Additional Code instructions are included in this display for I99.9. Check the code and parent instructions in the Code Book.

Code Also

Official

No Code Also instructions are included in this display for I99.9. Check the code and parent instructions in the Code Book.

Buddy Documentation Tip

HCC Buddy guidance
This is the least specific circulatory code and should be avoided when possible; query the provider for more specific diagnosis
Use only when documentation is truly insufficient to assign a more specific code

Current with CMS: FY2026 ICD-10-CM Apr 1 update (effective Apr 1 – Sep 30, 2026) · CMS-HCC V28, 100% phased in for payment year 2026. FY2027 code set already staged for October 1, 2026. How HCC Buddy stays current →

Is I99.9 an HCC code?

No. I99.9 is a billable ICD-10-CM code with no mapping under the current CMS-HCC V28 community payment model, and none under the ESRD, Part D RxHCC, or HHS-HCC models.

Code
I99.9
Description
Unspecified disorder of circulatory system
HCC (V28)
No CMS-HCC V28 mapping
RAF reference coefficient
—
Billable
Yes
Payment year
2026

Coder workflow notes

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What This Code Means

I99.9 is the ICD-10-CM diagnosis code for unspecified disorder of circulatory system. A heart or blood vessel disorder that is not specified or identified. I99.9 sits in the ICD-10-CM chapter for diseases of the circulatory system (i00-i99), within the section covering other and unspecified disorders of the circulatory system (i95-i99).

I99.9 is a billable ICD-10-CM code, but no current CMS-HCC V28 community payment mapping is shown, and none under the ESRD, Part D RxHCC, or HHS-HCC models. Do not assign risk adjustment value from this page when no source-backed mapping is shown; verify the applicable model and payment year.

This is the least specific circulatory code and should be avoided when possible; query the provider for more specific diagnosis.

HCC Buddy maintains structured V28 and V24 mapping, source-labeled coefficient references, and MEAT documentation criteria for I99.9 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

  • •This is the least specific circulatory code and should be avoided when possible; query the provider for more specific diagnosis
  • •Use only when documentation is truly insufficient to assign a more specific code

Child Codes

I99.8Other disorder of circulatory system
I99.9Unspecified disorder of circulatory system

Code Hierarchy

└I99Other and unspecified disorders of circulatory system└I99.9Unspecified disorder of circulatory system
└I99.9Unspecified disorder of circulatory system

Also searched as

  • I99 9
  • I999

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