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N99.531 ICD-10-CM Code: Infection of continent stoma of urinary tract

N99.531 is not a CMS-HCC payment code. MEAT criteria · RAF calculator · HCC coding software

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HCC Buddy Code Card

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FY 2026 Apr update / Diseases of the genitourinary system (N00-N99) / Intraoperative and postprocedural complications and disorders of genitourinary system, not elsewhere classified (N99)

N99.531

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

Infection of continent stoma of urinary tract

Infection or inflammation of a surgically created urine drainage opening that controls urine flow.

Buddy the Bee presenting code insight

Buddy Insight

Infection of a continent urinary stoma poses significant risks to the complex continence mechanism and may require extensive antibiotic therapy or surgical intervention.

CMS-HCC V28

N/A

Not mapped

CMS-HCC V24

HCC 176

RAF 0.582

ACA/HHS

N/A

Not mapped

ESRD/PACE

HCC 176

RAF 0.000

RXHCC

N/A

Not mapped

Code Book Path

Official
N99.5Complications of stoma of urinary tract
N99.53Complication of continent stoma of urinary tract
N99.531Infection of continent stoma of urinary tract

Inclusion Terms

Official

ICD-10-CM does not list inclusion terms for N99.531 in this effective period.

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for N99.531 in this effective period.

Related Child Codes

Official
N99.530Hemorrhage of continent stoma of urinary tract
N99.532Malfunction of continent stoma of urinary tract
N99.533Herniation of continent stoma of urinary tract
N99.534Stenosis of continent stoma of urinary tract
N99.538Other complication of continent stoma of urinary tract

Includes

Official

ICD-10-CM does not list Includes notes for N99.531 in this effective period.

Excludes 1

Official

ICD-10-CM does not list Excludes 1 notes for N99.531 in this effective period.

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for N99.531 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for N99.531 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for N99.531 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance
Documentation of continent urinary stoma presence and type
Signs and symptoms of infection
Culture results and organism identification
Impact on continence function

MEAT Support

HCC Buddy guidance
Documentation of continent urinary stoma presence and type
Signs and symptoms of infection
Culture results and organism identification
Impact on continence function

Audit Caution

HCC Buddy guidance
Confusing continent versus incontinent stoma types
Using general UTI codes instead of stoma-specific infection codes
Missing documentation of continent mechanism involvement
Incorrectly coding routine stoma care as infection

Common Mistakes

HCC Buddy guidance
N99.521 — Infection of incontinent external stoma (incontinent vs continent stoma)
N39.0 — Urinary tract infection, site not specified (general UTI vs stoma infection)
N99.530 — Hemorrhage of continent stoma (bleeding vs infection)
T83.59XA — Infection due to other urinary catheter (catheter vs stoma)

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 N99.531 an HCC code?

Yes. N99.531 maps to Complications of Specified Implanted Device or Graft under the V24 model but is not retained in V28.

Code
N99.531
Description
Infection of continent stoma of urinary tract
HCC (V28)
No CMS-HCC V28 mapping
RAF
Billable
Yes
Payment year
2026

HCC Category Mapping

V24HCC 176, Complications of Specified Implanted Device or Graft
0.582
ESRDHCC 176, Complications of Specified Implanted Device or Graft
0.000

Each model's RAF is its CMS base weight for that model's standard population, so weights are not directly comparable across models: CMS-HCC V28 and V24 use Community, Non-Dual, Aged; ESRD uses the dialysis continuing-enrollee model; RxHCC is the Part D continuing-enrollee, non-low-income, aged weight (a larger scale than CMS-HCC). ACA/HHS has no single weight — it varies by metal level. Actual per-patient RAF contribution depends on member segment, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains in use during the transition and for historical data.

Work N99.531 in the Code Book — tabular path, V28 RAF, and MEAT checklist →

MEAT Criteria for N99.531

For N99.531 to count as a valid HCC diagnosis in a given encounter, the provider's documentation must show MEAT: Monitor, Evaluate, Assess, or Treat. A diagnosis from a prior year does not carry forward automatically, it has to be re-documented and supported each calendar year.

  • MMonitor: signs, symptoms, disease progression, or lab trending documented in the note
  • EEvaluate: test results, medication response, or physical findings reviewed by the provider
  • AAssess: explicit mention in the assessment or plan with acknowledgment of status
  • TTreat: medication, referral, procedure, therapy, or counseling tied to the diagnosis

Only one of M/E/A/T is required to support the code, but the documentation must be specific enough to show that the provider actually addressed N99.531 during that encounter, not just copy-forwarded from a problem list.

Coder workflow notes

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What This Code Means

N99.531 is the ICD-10-CM diagnosis code for infection of continent stoma of urinary tract. Infection or inflammation of a surgically created urine drainage opening that controls urine flow. N99.531 sits in the ICD-10-CM chapter for diseases of the genitourinary system (n00-n99), within the section covering intraoperative and postprocedural complications and disorders of genitourinary system, not elsewhere classified (n99).

Under the older CMS-HCC V24 model, N99.531 maps to Complications of Specified Implanted Device or Graft (HCC 176) with a community, non-dual, aged base RAF weight of 0.582. V28 is the CMS-HCC risk adjustment model that reached 100% phase-in for payment year 2026, replacing V24 which was used during the PY2024–PY2025 transition.

Verify if infection is localized to stoma or involves deeper urinary tract structures. Because N99.531 maps to a payment HCC, the provider's documentation must satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's Medicare Advantage risk adjustment score. When documentation is ambiguous, coders should issue a provider query rather than assume the highest-specificity variant.

HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for N99.531 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

  • Verify if infection is localized to stoma or involves deeper urinary tract structures
  • Document causative organism if identified for complete clinical picture

Clinical Significance

Infection of a continent urinary stoma poses significant risks to the complex continence mechanism and may require extensive antibiotic therapy or surgical intervention. These infections can compromise the carefully constructed valve system and lead to loss of continence function.

Documentation Requirements

  • Documentation of continent urinary stoma presence and type
  • Signs and symptoms of infection
  • Culture results and organism identification
  • Impact on continence function
  • Antibiotic therapy prescribed
  • Response to treatment
  • Any structural damage to continence mechanism

Commonly Confused Codes

  • N99.521: Infection of incontinent external stoma (incontinent vs continent stoma)
  • N39.0: Urinary tract infection, site not specified (general UTI vs stoma infection)
  • N99.530: Hemorrhage of continent stoma (bleeding vs infection)
  • T83.59XA: Infection due to other urinary catheter (catheter vs stoma)

Child Codes

Code Hierarchy

N99.531 code history

Code setChange
FY2017 (effective Oct 1, 2016)Description revised

Source: official CMS ICD-10-CM order and addenda files, FY2016 through FY2027.

Because N99.531 maps to a payment HCC, the documentation must also satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's risk adjustment score.

Work N99.531 in HCC Buddy

Open N99.531 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 7 days to try everything, no card required.