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N99.512 ICD-10-CM Code: Cystostomy malfunction

Billing Status: YES. This is a valid, specific, and billable ICD-10-CM reference.

Coding at a Glance

Tabular directives
4 Excludes2
Risk adjustment
CMS-HCC V22 category 176

Inpatient Payment Groups (MS-DRG)

Potential MS-DRG participation — not a DRG assignment.

MS-DRGs this diagnosis helps define, as principal or secondary, per the CMS ICD-10-CM/PCS MS-DRG Definitions Manual v43, Appendix B.

  • MS-DRG 698 — OTHER KIDNEY AND URINARY TRACT DIAGNOSES WITH MCC (MDC 11)
  • MS-DRG 699 — OTHER KIDNEY AND URINARY TRACT DIAGNOSES WITH CC (MDC 11)
  • MS-DRG 700 — OTHER KIDNEY AND URINARY TRACT DIAGNOSES WITHOUT CC/MCC (MDC 11)

A diagnosis appearing in a group's logic does not by itself determine the DRG assigned to a stay; the grouper uses the full claim.

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for N99.512 in the official ICD-10-CM tabular list, quoted as published.

Source: CMS/CDC — ICD-10-CM Tabular ListRelease: FY2026Effective: October 1, 2025

Notes without a marker are published on N99.512 itself; “inherited from” names the category or block whose note applies here.

Excludes2 — Not Included Here

Conditions not covered by this code, but which may be reported alongside it when both are present.

Coder workflow for N99.512

MedCoder structured workflow — derived from this code’s own official record

Documentation check

The provider’s diagnostic statement
Codes are assigned from the provider’s documented diagnosis, not from clinical criteria, test values or a medication list (Guidelines I.A.19).

Official instructions as workflow

  • Excludes2 — not part of N99.512(4 notes)

    Coding workflow: The conditions named in this note are not included in N99.512. When the record documents both, both may be reported; the note is a boundary, not a prohibition.

    CompareT83.0, N30.4, M80.8, M81.8

    See the official tabular notes · Guidelines I.A.12.b

Every row is derived from this code’s own record — its title, tabular notes, 7th-character family and same-category siblings — with fixed MedCoder wording; nothing is inferred about a patient. The official notes and guideline text are in the sections each row links to, and they control.

Code Overview

Cystostomy malfunction is a billable ICD-10-CM diagnosis code (N99.512).

MedCoder summary Summary composed by MedCoder from this code's official ICD-10-CM record. The tabular instructional notes themselves appear verbatim below.

Indexed Clinical Terms (2)

Official source data — entries quoted as published, in the Index’s own lookup phrasing

Clinical term phrases from the official ICD-10-CM Index to Diseases and Injuries that map to this code. These are alphabetic-index entries shown as the Index writes them — lookup phrasing, not necessarily the wording of a final diagnosis.

Verify Before Coding

  • CC as a secondary diagnosis (FY2026). Can raise the stay's MS-DRG severity tier.

From the code registry, the Medicare Code Editor, and the MS-DRG Definitions Manual. Check it against a full claim in Claim Check.

Relationships & Classification

MedCoder structured relationships — computed from published CMS and AHRQ datasets

Other codes that name N99.512 or its code family, from the CMS ICD-10-CM tabular instructional notes. Tabular-note edges are stored at the code family level that carries each note.

Referenced by 2 Excludes1 notes: Z43 — Encounter for attention to artificial openings (via N99.5.-), Z93 — Artificial opening status (via N99.5.-).

These codes’ tabular lists mark this diagnosis as mutually exclusive — not reported together unless the conditions are documented as unrelated.

Referenced by 22 Excludes2 notes: T80 — Complications following infusion, transfusion and therapeutic injection (via N99.-), T80 — Complications following infusion, transfusion and therapeutic injection (via N99.5.-), T80-T88 — Complications of surgical and medical care, not elsewhere classified (T80-T88) (via N99.5.-), T80-T88 — Complications of surgical and medical care, not elsewhere classified (T80-T88) (via N99.-), T81 — Complications of procedures, not elsewhere classified (via N99.-), T81 — Complications of procedures, not elsewhere classified (via N99.5.-), T82 — Complications of cardiac and vascular prosthetic devices, implants and grafts (via N99.-), T82 — Complications of cardiac and vascular prosthetic devices, implants and grafts (via N99.5.-), T83 — Complications of genitourinary prosthetic devices, implants and grafts (via N99.-), T83 — Complications of genitourinary prosthetic devices, implants and grafts (via N99.5.-), T83.0 — Mechanical complication of urinary catheter (via N99.5.-), T83.51 — Infection and inflammatory reaction due to urinary catheter (via N99.5.-), T84 — Complications of internal orthopedic prosthetic devices, implants and grafts (via N99.5.-), T84 — Complications of internal orthopedic prosthetic devices, implants and grafts (via N99.-), T85 — Complications of other internal prosthetic devices, implants and grafts (via N99.-), T85 — Complications of other internal prosthetic devices, implants and grafts (via N99.5.-), T86 — Complications of transplanted organs and tissue (via N99.5.-), T86 — Complications of transplanted organs and tissue (via N99.-), T87 — Complications peculiar to reattachment and amputation (via N99.-), T87 — Complications peculiar to reattachment and amputation (via N99.5.-), +2 more.

These codes’ tabular lists name this diagnosis as distinct — both may be reported when both are documented.

MS-DRG Grouper Relationships (FY2026)

Potential MS-DRG participation — not a DRG assignment.

FY2026 MS-DRG: CC — Complication or Comorbidity. Reported as a secondary diagnosis, this code raises the stay's MS-DRG severity tier — except when the principal diagnosis is one of 116 clinically related codes on its CMS exclusion list.

Named in the grouper logic of 3 MS-DRGs: DRG 698 (MDC 11), DRG 699 (MDC 11), DRG 700 (MDC 11).

From the CMS MS-DRG Definitions Manual (Appendices B and C). Actual DRG assignment depends on the complete claim.

Clinical classification (AHRQ CCSR):GEN026 — Postprocedural or postoperative genitourinary system complication (default).

Clinical Classifications Software Refined (CCSR) for ICD-10-CM Diagnoses. Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality.

Related Codes

Same clinical process (MS-DRG)

Acts as CC — raises the severity of other admissions. CMS groups these diagnoses into one MS-DRG principal-diagnosis exclusion process — a CC/MCC on this list never raises severity when the principal diagnosis is also on it.

L76.82 — Other postprocedural complications of skin and subcutaneous tissue, M96.89 — Other intraoperative and postprocedural complications and disorders of the musculoskeletal system, N32.89 — Other specified disorders of bladder, N98.1 — Hyperstimulation of ovaries, N98.2 — Complications of attempted introduction of fertilized ovum following in vitro fertilization, N98.3 — Complications of attempted introduction of embryo in embryo transfer, N98.8 — Other complications associated with artificial fertilization, N98.9 — Complication associated with artificial fertilization, unspecified, N99.510 — Cystostomy hemorrhage, N99.511 — Cystostomy infection, N99.518 — Other cystostomy complication, T81.82XA — Emphysema (subcutaneous) resulting from a procedure, initial encounter, T81.89XA — Other complications of procedures, not elsewhere classified, initial encounter, T81.9XXA — Unspecified complication of procedure, initial encounter, T83.010A — Breakdown (mechanical) of cystostomy catheter, initial encounter, T83.020A — Displacement of cystostomy catheter, initial encounter, T83.030A — Leakage of cystostomy catheter, initial encounter, T83.090A — Other mechanical complication of cystostomy catheter, initial encounter, T83.110A — Breakdown (mechanical) of urinary electronic stimulator device, initial encounter, T83.111A — Breakdown (mechanical) of implanted urinary sphincter, initial encounter, +95 more

Same clinical category (CCSR)

AHRQ's Clinical Classifications Software groups these diagnoses under the same clinical category (Postprocedural or postoperative genitourinary system complication).

N99.113 — Postprocedural anterior bulbous urethral stricture, male, N99.114 — Postprocedural urethral stricture, male, unspecified, N99.115 — Postprocedural fossa navicularis urethral stricture, N99.116 — Postprocedural urethral stricture, male, overlapping sites, N99.12 — Postprocedural urethral stricture, female, N99.2 — Postprocedural adhesions of vagina, N99.3 — Prolapse of vaginal vault after hysterectomy, N99.4 — Postprocedural pelvic peritoneal adhesions, N99.510 — Cystostomy hemorrhage, N99.511 — Cystostomy infection, N99.518 — Other cystostomy complication, N99.520 — Hemorrhage of incontinent external stoma of urinary tract, N99.521 — Infection of incontinent external stoma of urinary tract, N99.522 — Malfunction of incontinent external stoma of urinary tract, N99.523 — Herniation of incontinent stoma of urinary tract, N99.524 — Stenosis of incontinent stoma of urinary tract, N99.528 — Other complication of incontinent external stoma of urinary tract, N99.530 — Hemorrhage of continent stoma of urinary tract, N99.531 — Infection of continent stoma of urinary tract, N99.532 — Malfunction of continent stoma of urinary tract, +27 more

Same Index main term, other category

The ICD-10-CM Index to Diseases and Injuries files this code under the main term “Malfunction”; these codes share that main term but sit in a different category of the Tabular List.

J95.03 — Malfunction of tracheostomy stoma (tracheostomy), K31.89 — Other diseases of stomach and duodenum (gastroenteric), K94.03 — Colostomy malfunction (colostomy), K94.13 — Enterostomy malfunction (ileostomy), K94.23 — Gastrostomy malfunction (gastrostomy), K94.33 — Esophagostomy malfunction (esophagostomy), T82.09 — Other mechanical complication of heart valve prosthesis (valve, heart), T82.110 — Breakdown (mechanical) of cardiac electrode (cardiac electronic device, electrode), T82.111 — Breakdown (mechanical) of cardiac pulse generator (battery) (cardiac electronic device, pulse generator), T82.118 — Breakdown (mechanical) of other cardiac electronic device (cardiac electronic device, specified type NEC), T82.119 — Breakdown (mechanical) of unspecified cardiac electronic device (cardiac electronic device), T82.41 — Breakdown (mechanical) of vascular dialysis catheter (catheter device NEC, dialysis), T82.514 — Breakdown (mechanical) of infusion catheter (catheter device NEC, infusion NEC), T83.010 — Breakdown (mechanical) of cystostomy catheter (cystostomy, catheter), T83.018 — Breakdown (mechanical) of other urinary catheter (catheter device NEC, urinary), T85.01 — Breakdown (mechanical) of ventricular intracranial (communicating) shunt (ventricular), T85.611 — Breakdown (mechanical) of intraperitoneal dialysis catheter (catheter device NEC, dialysis, intraperitoneal), T85.615 — Breakdown (mechanical) of other nervous system device, implant or graft (intrathecal infusion pump), T85.618 — Breakdown (mechanical) of other specified internal prosthetic devices, implants and grafts (catheter device NEC), T85.690 — Other mechanical complication of cranial or spinal infusion catheter (catheter device NEC, infusion NEC, spinal)

Lab tests where this diagnosis supports Medicare coverage (NCD)

Medicare's National Coverage Determination (NCD) program lists this diagnosis as medical justification for these lab tests.

Partial Thromboplastin Time (PTT) Test, Prothrombin Time Test and INR (PT/INR)

Contextual Map

Every relationship of N99.512 in one view: hierarchy, official tabular instructions in both directions, clinical classification, risk adjustment, MS-DRG participation, index terms and change history — each edge carrying the CMS source it derives from.

Run N99.512 with these 6 related codes in Claim Check

Hierarchy

Referenced by Excludes1 notes

Referenced by Excludes2 notes (22)

Clinical classification (CCSR)

MS-DRG Grouper

MDC crossing

  • MDC 11 — Diseases and Disorders of the Kidney and Urinary Tract[MDC crossing]: “Diseases and Disorders of the Kidney and Urinary Tract — the grouper's crossing between diagnoses and procedures: a principal diagnosis sets the MDC, and same-MDC procedures move the stay to its surgical DRGs. 3,574 same-MDC procedures group here; browse them on the MDC page.”— CMS MS-DRG Definitions Manual · FY2026

Index entries

  • Complication (s) (from) (of), cystostomy (stoma), malfunction[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Malfunction, cystostomy (stoma)[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026

Nearest codes (40)

Change history

  • FY2016 — In the code set at ICD-10-CM adoption [Change history]— CMS release files (code change ledger) · icd10cm-fy2016

Sources for this page

Codes, titles, notes, index terms and mappings on this page are transcribed from the datasets below. Relationships MedCoder computed and text MedCoder wrote are labelled where they appear.

Code, title, tabular notes and index terms Official source data
CMS/CDC ICD-10-CM FY2026 tabular list, index and tables, effective October 1, 2025 Release, file and checksum · Publisher’s page
Claim edits Official source data
CMS Definitions of Medicare Code Edits — v43.1 (April 2026) Release, file and checksum · Publisher’s page
Inpatient payment groups Official source data
CMS MS-DRG Definitions Manual (incl. Appendix B diagnosis index, Appendix C CC/MCC list, Appendix E procedure index) and IPPS Final Rule tables — v43 Release, file and checksum · Publisher’s page
Change history and date-of-service validity Official source data
CMS ICD-10-CM release addenda, ingested release by release into the change ledger Release, file and checksum · Publisher’s page
Comparisons, relationships and the contextual map MedCoder structured relationship
Computed by MedCoder from the tabular notes and tables above; every derived relationship is marked as derived where it appears
Summary and FAQ answers MedCoder explanation
Written by MedCoder to explain the sources above: drafted with AI assistance, checked by a person against the release files, and labelled as MedCoder text where it appears. Not official text.

Labels on this page: Official source data · MedCoder structured relationship · MedCoder explanation. How to read the labels · All data sources and release dates

Change history

  • FY2016 — October 1, 2015
    In the code set at ICD-10-CM adoption
    Cystostomy malfunction

No changes since FY2016 — additions, deletions, description changes and billable-status changes are tracked through FY2027 (effective October 1, 2026), and none are recorded for this code. Note changes are tracked from FY2027 only.

Nearest Codes in This Family

Official ICD-10-CM classifications closest to N99.512 in its code family, with their registry titles.

View all codes in the N99 family