N99.512 ICD-10-CM Code: Cystostomy malfunction
N99.512 is not a CMS-HCC payment code. MEAT criteria · RAF Calculator · HCC Buddy coding tools
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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)
N99.512
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceCystostomy malfunction
The cystostomy stops functioning properly, meaning urine is not draining correctly through the surgically created bladder opening. This may involve blockage, leakage, or other mechanical failure.
Buddy Insight
Cystostomy malfunction represents a serious complication requiring immediate intervention to restore proper urinary drainage and prevent infection or kidney damage.
CMS-HCC V28
N/A—
Not mapped
CMS-HCC V24
HistoricalHistorical
Not used for CY2026 payment
ACA/HHS
N/A—
Not mapped
ESRD/PACE
MappedHCC 176
Code-level coefficient reference
RXHCC
N/A—
Not mapped
Code Book Path
Inclusion Terms
OfficialNo inclusion terms are included in this display for N99.512. Check the code and parent instructions in the Code Book.
Excludes 2
Official- certain conditions originating in the perinatal period (P04-P96)Inherited from N00-N99, N99, N99.5
- certain infectious and parasitic diseases (A00-B99)Inherited from N00-N99, N99, N99.5
- complications of pregnancy, childbirth and the puerperium (O00-O9A)Inherited from N00-N99, N99, N99.5
- congenital malformations, deformations and chromosomal abnormalities (Q00-Q99)Inherited from N00-N99, N99, N99.5
- endocrine, nutritional and metabolic diseases (E00-E88)Inherited from N00-N99, N99, N99.5
- injury, poisoning and certain other consequences of external causes (S00-T88)Inherited from N00-N99, N99, N99.5
- neoplasms (C00-D49)Inherited from N00-N99, N99, N99.5
- symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)Inherited from N00-N99, N99, N99.5
- irradiation cystitis (N30.4-)Inherited from N00-N99, N99, N99.5
- postoophorectomy osteoporosis with current pathological fracture (M80.8-)Inherited from N00-N99, N99, N99.5
- postoophorectomy osteoporosis without current pathological fracture (M81.8)Inherited from N00-N99, N99, N99.5
- mechanical complication of urinary catheter (T83.0-)Inherited from N00-N99, N99, N99.5
Related Codes
Includes
OfficialNo Includes notes are included in this display for N99.512. Check the code and parent instructions in the Code Book.
Excludes 1
OfficialNo Excludes 1 notes are included in this display for N99.512. Check the code and parent instructions in the Code Book.
Code First
OfficialNo Code First sequencing instructions are included in this display for N99.512. Check the code and parent instructions in the Code Book.
Use Additional
OfficialNo Use Additional Code instructions are included in this display for N99.512. Check the code and parent instructions in the Code Book.
Code Also
OfficialNo Code Also instructions are included in this display for N99.512. Check the code and parent instructions in the Code Book.
Buddy Documentation Tip
MEAT Support
Audit Caution
Common Mistakes
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 N99.512 an HCC code?
N99.512 is not in the CMS-HCC V28 or V24 community payment model. N99.512 has a separate mapping under the CMS-HCC ESRD model (HCC 176 (Complications of Specified Implanted Device or Graft)); the applicable result needs member context.
- Code
- N99.512
- Description
- Cystostomy malfunction
- HCC (V28)
- No CMS-HCC V28 mapping
- RAF reference coefficient
- —
- Billable
- Yes
- Payment year
- 2026
HCC Category Mapping
These are source-labeled model coefficients, not member totals. A category may still be removed by hierarchy or model cleanup rules. 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 context, hierarchy and cleanup rules, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains available for historical review.
Work N99.512 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →
MEAT review for N99.512
For N99.512, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule.
- 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
Coder workflow notes
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What This Code Means
N99.512 is the ICD-10-CM diagnosis code for cystostomy malfunction. The cystostomy stops functioning properly, meaning urine is not draining correctly through the surgically created bladder opening. This may involve blockage, leakage, or other mechanical failure. N99.512 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).
N99.512 has no mapping under the CMS-HCC V28 or V24 community payment models. N99.512 has a separate mapping under the CMS-HCC ESRD model (HCC 176 (Complications of Specified Implanted Device or Graft)); the applicable result needs member context. Do not assign V28 risk adjustment value from this page; verify the applicable model and payment year before using this code for risk adjustment.
Document the specific type of malfunction (obstruction, leakage, displacement) when available.
HCC Buddy maintains structured V28 and V24 mapping, source-labeled coefficient references, and MEAT documentation criteria for N99.512 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Document the specific type of malfunction (obstruction, leakage, displacement) when available
- •Ensure the cystostomy is confirmed to be present and the malfunction is not due to patient error
Clinical Significance
Cystostomy malfunction represents a serious complication requiring immediate intervention to restore proper urinary drainage and prevent infection or kidney damage. This condition significantly impacts patient quality of life and requires ongoing specialized care management.
Documentation Requirements
- ✓Documentation of existing cystostomy tube or catheter
- ✓Description of specific malfunction (blockage, leakage, dislodgement)
- ✓Clinical signs and symptoms of malfunction
- ✓Date when malfunction was identified
- ✓Impact on urinary drainage function
- ✓Any interventions attempted or planned
- ✓Provider assessment of the complication severity
Commonly Confused Codes
- •N99.511: Cystostomy hemorrhage (bleeding from cystostomy site)
- •T83.010A: Breakdown of cystostomy catheter, initial encounter (device-specific complication)
- •N32.9: Bladder disorder, unspecified (not specifically cystostomy-related)
- •N99.518: Other cystostomy complication (non-malfunction complications)