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M31.10 ICD-10-CM Code: Thrombotic microangiopathy, unspecified

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

Coding at a Glance

Tabular directives
4 inclusion terms · 1 Excludes1
Risk adjustment
CMS-HCC V28: 1 category · CMS-HCC V22 category 40 · RxHCC V08 category 84

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 545 — CONNECTIVE TISSUE DISORDERS WITH MCC (MDC 08)
  • MS-DRG 546 — CONNECTIVE TISSUE DISORDERS WITH CC (MDC 08)
  • MS-DRG 547 — CONNECTIVE TISSUE DISORDERS WITHOUT CC/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.

Risk Adjustment (CMS-HCC)

Payment categories this diagnosis maps to under CMS-HCC V28, payment year 2026.

  • HCC 112 — Immune Thrombocytopenia and Specified Coagulation Defects and Hemorrhagic Conditions

Other models: CMS-HCC V22 HCC 40 · RxHCC V08 HCC 84

Risk scores depend on the enrollee's full accepted diagnosis set and segment; a category mapping alone does not determine payment.

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for M31.10 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 M31.10 itself; “inherited from” names the category or block whose note applies here.

Includes

Conditions the official ICD-10-CM tabular list includes under this code.

  • autoimmune disease NOS
  • collagen (vascular) disease NOS
  • systemic autoimmune disease
  • systemic collagen (vascular) disease

Source: inherited from M30-M36

Excludes1 — Not Coded Here

Conditions generally not reported together with this code (Excludes1) -- an error unless the two conditions are documented as unrelated to each other (ICD-10-CM Official Guidelines, Section I.A.12.a).

  • autoimmune disease, single organ or single cell-type -code to relevant condition category

Source: inherited from M30-M36

Coder workflow for M31.10

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

Before you code M31.10

  1. Unspecified does not mean incorrect. When the record gives no greater specificity, M31.10 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).

    ReviewM31.11, M31.19

    See the relationships section · Guide: Other vs unspecified (NEC vs NOS) →

  2. Check the Excludes1 note: if the documentation supports a condition named there, do not simply proceed with M31.10. Excludes1 conditions are not reported together with this code unless the record shows they are unrelated (Guidelines I.A.12.a).

    See the official tabular notes

Choose the right path

  1. Does the record document the detail a more specific sibling code needs?
    Yes → Review the specific siblings in this subcategory.
    No → Continue — M31.10 is appropriate when the documentation goes no further.

    ReviewM31.11, M31.19

  2. Does the documentation support a condition named in M31.10’s Excludes1 note?
    Yes → Do not simply proceed: review the excluded code. Both are reported only when the record shows the two conditions are unrelated.
    No → Continue.

Consider M31.10. 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.

Official instructions as workflow

  • Excludes1 — check before selecting M31.10(1 note)

    Coding workflow: If the documentation supports a condition named in this note, do not simply proceed with M31.10: the two are not reported together. The one exception is when the record shows the two conditions are unrelated to each other.

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

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).

ReviewM31.11, M31.19

Documentation: Both the condition M31.10 describes and a condition named in its Excludes1 note are documented for the same encounter.

Coding question: Can both codes be reported?

Path: Review the Excludes1 note and the excluded code, and look for a provider statement on whether the two conditions are related.

Reason: Excludes1 means the two are not coded together; the exception is when the record shows the conditions are unrelated to each other (Guidelines I.A.12.a).

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

Thrombotic microangiopathy, unspecified is a billable ICD-10-CM diagnosis code (M31.10).

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.

Verify Before Coding

  • MCC 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 M31.10 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: L94 — Other localized connective tissue disorders (via M31.-).

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

Referenced by 2 Excludes2 notes across 2 chapters: I77 — Other disorders of arteries and arterioles (via M31.-), J82 — Pulmonary eosinophilia, not elsewhere classified (via M31.-).

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

Referenced by 1 Code First instruction: J84.170 — Interstitial lung disease with progressive fibrotic phenotype in diseases classified elsewhere (via M31.-).

Each of these codes carries a Code First note naming this condition — when that code is reported, THIS code is sequenced first, ahead of it.

MS-DRG Grouper Relationships (FY2026)

Potential MS-DRG participation — not a DRG assignment.

FY2026 MS-DRG: MCC — Major 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 25 clinically related codes on its CMS exclusion list.

Named in the grouper logic of 3 MS-DRGs: DRG 545 (MDC 08), DRG 546 (MDC 08), DRG 547 (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):MUS024 — Systemic lupus erythematosus and connective tissue disorders (default); CIR037 — Vasculitis.

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 MCC — 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.

E11.51 — Type 2 diabetes mellitus with diabetic peripheral angiopathy without gangrene, E11.52 — Type 2 diabetes mellitus with diabetic peripheral angiopathy with gangrene, E13.51 — Other specified diabetes mellitus with diabetic peripheral angiopathy without gangrene, E13.52 — Other specified diabetes mellitus with diabetic peripheral angiopathy with gangrene, I27.841 — Fontan-associated lymphatic dysfunction, I27.848 — Other Fontan-associated condition, I27.849 — Fontan related circulation, unspecified, I99.8 — Other disorder of circulatory system, I99.9 — Unspecified disorder of circulatory system, M30.0 — Polyarteritis nodosa, M30.1 — Polyarteritis with lung involvement [Churg-Strauss], M30.2 — Juvenile polyarteritis, M30.3 — Mucocutaneous lymph node syndrome [Kawasaki], M30.8 — Other conditions related to polyarteritis nodosa, M31.0 — Hypersensitivity angiitis, M31.11 — Hematopoietic stem cell transplantation-associated thrombotic microangiopathy [HSCT-TMA], M31.19 — Other thrombotic microangiopathy, M31.5 — Giant cell arteritis with polymyalgia rheumatica, M31.6 — Other giant cell arteritis, M31.7 — Microscopic polyangiitis, +4 more

Same CMS-HCC risk category (V28)

CMS maps these diagnoses to the same Hierarchical Condition Category (Immune Thrombocytopenia and Specified Coagulation Defects and Hemorrhagic Conditions) for risk-adjusted payment.

D68.00 — Von Willebrand disease, unspecified, D68.01 — Von Willebrand disease, type 1, D68.020 — Von Willebrand disease, type 2A, D68.021 — Von Willebrand disease, type 2B, D68.022 — Von Willebrand disease, type 2M, D68.023 — Von Willebrand disease, type 2N, D68.029 — Von Willebrand disease, type 2, unspecified, D68.03 — Von Willebrand disease, type 3, D68.04 — Acquired von Willebrand disease, D68.09 — Other von Willebrand disease, D68.1 — Hereditary factor XI deficiency, D68.2 — Hereditary deficiency of other clotting factors, D68.311 — Acquired hemophilia, D69.1 — Qualitative platelet defects, D69.3 — Immune thrombocytopenic purpura, D69.41 — Evans syndrome, D69.42 — Congenital and hereditary thrombocytopenia purpura, D69.49 — Other primary thrombocytopenia, D75.84 — Other platelet-activating anti-PF4 disorders, M31.19 — Other thrombotic microangiopathy

Related risk categories

These categories interact through CMS's HCC hierarchy — one can suppress the other's risk-adjustment weight when both are present on a claim.

Hemophilia, Male

Same clinical category (CCSR)

AHRQ's Clinical Classifications Software groups these diagnoses under the same clinical categories (Systemic lupus erythematosus and connective tissue disorders, Vasculitis).

M05.272 — Rheumatoid vasculitis with rheumatoid arthritis of left ankle and foot, M05.279 — Rheumatoid vasculitis with rheumatoid arthritis of unspecified ankle and foot, M05.29 — Rheumatoid vasculitis with rheumatoid arthritis of multiple sites, M30.0 — Polyarteritis nodosa, M30.1 — Polyarteritis with lung involvement [Churg-Strauss], M30.2 — Juvenile polyarteritis, M30.3 — Mucocutaneous lymph node syndrome [Kawasaki], M30.8 — Other conditions related to polyarteritis nodosa, M31.0 — Hypersensitivity angiitis, M31.1 — Thrombotic microangiopathy, M31.11 — Hematopoietic stem cell transplantation-associated thrombotic microangiopathy [HSCT-TMA], M31.19 — Other thrombotic microangiopathy, M31.2 — Lethal midline granuloma, M31.30 — Wegener's granulomatosis without renal involvement, M31.31 — Wegener's granulomatosis with renal involvement, M31.4 — Aortic arch syndrome [Takayasu], M31.5 — Giant cell arteritis with polymyalgia rheumatica, M31.6 — Other giant cell arteritis, M31.7 — Microscopic polyangiitis, M31.8 — Other specified necrotizing vasculopathies, +101 more

Same Index main term, other category

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

I73.9 — Peripheral vascular disease, unspecified

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.

HIV Screening Test, Partial Thromboplastin Time (PTT) Test

Contextual Map

Every relationship of M31.10 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 M31.10 with these 4 related codes in Claim Check

Hierarchy

Referenced by Excludes1 notes

Referenced by Excludes2 notes

Referenced by Code First instructions

Clinical classification (CCSR)

Risk adjustment (CMS-HCC)

  • HCC 112 — Immune Thrombocytopenia and Specified Coagulation Defects and Hemorrhagic Conditions [CMS-HCC]— CMS-HCC V28 · 2026

MS-DRG Grouper

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

  • Microangiopathy (peripheral), thrombotic[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026

Nearest codes (15)

Change history

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
Risk adjustment Official source data
2026 Mid-Year Final ICD-10 Mappings + Model Software (cms.gov/files/zip/2026-midyear-final-icd-10-mappings.zip, 2026-midyear-final-model-software.zip) — CMS-HCC V28, PY2026 mid-year final release 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. "M31.10 — Thrombotic microangiopathy, unspecified." ICD-10-CM FY2026. https://medcoder.ai/icd10/code/m31.10-thrombotic-microangiopathy-unspecified

Change history

  • FY2022 — October 1, 2021
    Added to the code set
    Thrombotic microangiopathy, unspecified
    FY2022 changes

Nearest Codes in This Family

Official ICD-10-CM classifications closest to M31.10 in its code family, with their registry titles.

View all codes in the M31 family