Name: Crystal arthropathy, unspecified
Creator: MedCoder.ai

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

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 553 — BONE DISEASES AND ARTHROPATHIES WITH MCC (MDC 08)
MS-DRG 554 — BONE DISEASES AND ARTHROPATHIES WITHOUT MCC (MDC 08)

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.

Coder workflow for M11.9

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

Before you code M11.9

Unspecified does not mean incorrect. When the record gives no greater specificity, M11.9 may be the appropriate code. Check the record for detail that supports a more specific sibling. An unspecified code is for records that do not provide the detail a more specific code needs; a query, not an assumption, is the route to specificity (Guidelines I.A.9.b, I.B.18).
ReviewM11.8
See the relationships section · Guide: Other vs unspecified (NEC vs NOS) →

Choose the right path

Does the record document the detail a more specific sibling code needs?
Yes → Review the specific siblings in this subcategory.
No → Continue — M11.9 is appropriate when the documentation goes no further.
ReviewM11.8

Consider M11.9. Then confirm the code is valid for the date of service in the Verify section.

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).
Any detail beyond this code’s title: What the record states that a more specific sibling code would capture — or its absence, which itself supports the unspecified code.

Coding decision scenarios

Pattern scenarios for this code’s structure — decision rules, not clinical cases

Documentation: The provider documents the condition in the terms of this code’s title and records no further detail.

Coding question: Is a more specific sibling code supportable?

Path: Review the specific siblings in this subcategory and what each requires the record to state.

Reason: A more specific code needs documentation of the distinguishing element; without it the unspecified code is appropriate, and a provider query is the route to specificity (Guidelines I.A.9.b, I.B.18).

ReviewM11.8

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

Crystal arthropathy, unspecified is a billable ICD-10-CM diagnosis code (M11.9).

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 (1)

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.

Arthritis, arthritic (acute) (chronic) (nonpyogenic) (subacute), in (due to), crystals

Verify Before Coding

No Medicare Code Editor or MS-DRG Definitions Manual restrictions apply to this code.

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 M11.9 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 1 Excludes1 note: E83.5 — Disorders of calcium metabolism (via M11.-).

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

MS-DRG Grouper Relationships (FY2026)

Potential MS-DRG participation — not a DRG assignment.

FY2026 MS-DRG: not on the CMS CC/MCC list — as a secondary diagnosis this code does not change MS-DRG severity for that release.

Named in the grouper logic of 2 MS-DRGs: DRG 553 (MDC 08), DRG 554 (MDC 08).

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

Clinical classification (AHRQ CCSR):MUS034 — Crystal arthropathies (excluding gout) (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 category (CCSR)

AHRQ's Clinical Classifications Software groups these diagnoses under the same clinical category (Crystal arthropathies (excluding gout)).

Same Index main term, other category

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

Contextual Map

Every relationship of M11.9 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 M11.9 with this related code in Claim Check

Hierarchy

M00-M99 — Chapter 13: Diseases of the Musculoskeletal System and Connective Tissue (M00-M99) (M00-M99)[Hierarchy]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
M00-M25 — Arthropathies[Hierarchy]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
M05-M14 — Inflammatory polyarthropathies[Hierarchy]— CMS ICD-10-CM tabular structure · icd10cm-fy2026

Referenced by Excludes1 notes

E83.5 — Disorders of calcium metabolism[Excludes1](via M11.-): “chondrocalcinosis (M11.1-M11.2)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026

Clinical classification (CCSR)

MUS034 — Crystal arthropathies (excluding gout)[CCSR]— AHRQ CCSR for ICD-10-CM Diagnoses (HCUP)

MS-DRG Grouper

DRG 553 — BONE DISEASES AND ARTHROPATHIES WITH MCC[MS-DRG]: “BONE DISEASES AND ARTHROPATHIES WITH MCC (MDC 08)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2026
DRG 554 — BONE DISEASES AND ARTHROPATHIES WITHOUT MCC[MS-DRG]: “BONE DISEASES AND ARTHROPATHIES WITHOUT MCC (MDC 08)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2026

MDC crossing

MDC 08 — Diseases and Disorders of the Musculoskeletal System and Connective Tissue[MDC crossing]: “Diseases and Disorders of the Musculoskeletal System and Connective Tissue — 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. 18,508 same-MDC procedures group here; browse them on the MDC page.”— CMS MS-DRG Definitions Manual · FY2026

Index entries

Arthritis, arthritic (acute) (chronic) (nonpyogenic) (subacute), in (due to), crystals[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026

Nearest codes (40)

M11 — Other crystal arthropathies[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
M11.262 — Other chondrocalcinosis, left knee[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
M11.269 — Other chondrocalcinosis, unspecified knee[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
M11.27 — Other chondrocalcinosis, ankle and foot[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
M11.271 — Other chondrocalcinosis, right ankle and foot[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
M11.272 — Other chondrocalcinosis, left ankle and foot[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
M11.279 — Other chondrocalcinosis, unspecified ankle and foot[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
M11.28 — Other chondrocalcinosis, vertebrae[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
and 32 more

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

Cite this page

Reference this page in a research guide, syllabus or article. The release is included because code content changes each year.

MedCoder.ai. "M11.9 — Crystal arthropathy, unspecified." ICD-10-CM FY2026. https://medcoder.ai/icd10/code/m11.9-crystal-arthropathy-unspecified

Change history

FY2016 — October 1, 2015
In the code set at ICD-10-CM adoption
Crystal arthropathy, unspecified

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 M11.9 in its code family, with their registry titles.

View all codes in the M11 family

M11.9 ICD-10-CM Code: Crystal arthropathy, unspecified

Inpatient Payment Groups (MS-DRG)

Coder workflow for M11.9

Before you code M11.9

Choose the right path

Documentation check

Coding decision scenarios

Code Overview

Indexed Clinical Terms (1)

Verify Before Coding

Relationships & Classification

MS-DRG Grouper Relationships (FY2026)

Related Codes

Same clinical category (CCSR)

Same Index main term, other category

Contextual Map

Hierarchy

Referenced by Excludes1 notes

Clinical classification (CCSR)

MS-DRG Grouper

MDC crossing

Index entries

Nearest codes (40)

Change history

Sources for this page

Cite this page

Change history

Nearest Codes in This Family