N99.518 ICD-10-CM Code: Other cystostomy complication
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)
N99.518
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceOther cystostomy complication
A complication occurs related to a cystostomy that is not bleeding, infection, or malfunction. Examples include granulation tissue, pain, or other issues at the stoma site.
Buddy Insight
Other cystostomy complications encompass various non-bleeding, non-infectious, non-malfunction issues that still require medical management and monitoring.
CMS-HCC V28
00
RAF 0
CMS-HCC V24
MappedHCC 176
RAF 0.529
ACA/HHS
00
RAF 0
ESRD/PACE
MappedHCC 176
RAF 0.0
RXHCC
00
RAF 0
Code Trumping
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Code Book Path
Inclusion Terms
OfficialICD-10-CM does not list inclusion terms for N99.518 in this effective period.
Excludes 2
OfficialICD-10-CM does not list Excludes 2 notes for N99.518 in this effective period.
Related Child Codes
Includes
OfficialICD-10-CM does not list Includes notes for N99.518 in this effective period.
Excludes 1
OfficialICD-10-CM does not list Excludes 1 notes for N99.518 in this effective period.
Code First
OfficialICD-10-CM does not list Code First sequencing instructions for N99.518 in this effective period.
Use Additional
OfficialICD-10-CM does not list Use Additional Code instructions for N99.518 in this effective period.
Code Also
OfficialICD-10-CM does not list Code Also instructions for N99.518 in this effective period.
Buddy Documentation Tip
MEAT Support
Audit Caution
Common Mistakes
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 N99.518 an HCC code?
Yes. N99.518 maps to Complications of Specified Implanted Device or Graft under the V24 model but is not retained in V28.
HCC Category Mapping
RAF weights shown are the community, non-dual, aged base weights from the CMS risk adjustment model file. 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.
MEAT Criteria for N99.518
For N99.518to 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 N99.518 during that encounter, not just copy-forwarded from a problem list.
What This Code Means
N99.518 is the ICD-10-CM diagnosis code for other cystostomy complication. A complication occurs related to a cystostomy that is not bleeding, infection, or malfunction. Examples include granulation tissue, pain, or other issues at the stoma site. N99.518 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, N99.518 maps to Complications of Specified Implanted Device or Graft (HCC 176) with a community, non-dual, aged base RAF weight of 0.529. 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.
Use this code only when the specific complication does not fit N99.510, N99.511, or N99.512. Because N99.518 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 N99.518 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
Clinical Significance
Other cystostomy complications encompass various non-bleeding, non-infectious, non-malfunction issues that still require medical management and monitoring. These complications indicate ongoing complexity in urological care and potential need for specialized interventions.
Documentation Requirements
- ✓Documentation of existing cystostomy
- ✓Specific description of the complication type
- ✓Clinical manifestations or symptoms
- ✓Duration and progression of the complication
- ✓Any associated pain or discomfort
- ✓Treatment interventions provided or planned
- ✓Impact on patient's urinary function or quality of life