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M31.1 ICD-10-CM Code: Thrombotic microangiopathy

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Billing Status: NO. This is a non-billable ICD-10-CM code: report a more specific billable code beneath it.

Coding at a Glance

Tabular directives
4 inclusion terms · 1 Excludes1

Not billable · FY2027A non-billable heading in the tabular list: report a more specific code beneath it.

What you need to know

Source: CMS/NCHS Official ICD-10-CM tabular notes, quoted. From the CMS/NCHS tabular list for the release in force. A note the category or block publishes applies to this code too; the Instructions section marks which is which.

Excludes1Never report with this code
  • autoimmune disease, single organ or single cell-type -code to relevant condition category
IncludesWhat this code covers
  • autoimmune disease NOS
  • collagen (vascular) disease NOS
  • systemic autoimmune disease
  • systemic collagen (vascular) disease

CompareCheck ClaimView Related Codes

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for M31.1 in the official ICD-10-CM tabular list, quoted as published.

Source: CMS/CDC — ICD-10-CM Tabular ListRelease: FY2027Effective: October 1, 2026

Trace:FY2027 changesChange historyRelease, file and checksum

Notes without a marker are published on M31.1 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 M31.1

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

Before you code M31.1

  1. M31.1 is not reportable as written. Select the more specific code beneath it that the documentation supports. Codes are reported to the highest level of specificity the classification provides (Guidelines I.B.2).

    ReviewM31.10, M31.11, M31.19

    See the relationships section · Guide: How to choose an ICD-10-CM code →

  2. Check the Excludes1 note: if the documentation supports a condition named there, do not simply proceed with M31.1. 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 documentation support one of the more specific codes beneath M31.1?
    Yes → Select that code and continue the checks below on its own page.
    No → M31.1 cannot be reported as written; query for the specificity its subcategory needs.

    ReviewM31.10, M31.11, M31.19

  2. Does the documentation support a condition named in M31.1’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 M31.1. 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).

Official instructions as workflow

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

    Coding workflow: If the documentation supports a condition named in this note, do not simply proceed with M31.1: 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: Both the condition M31.1 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.

Coding context

The comparisons, hierarchy, index entries, guidelines, relationships, risk-adjustment and coverage context a coder commonly needs. Each section names whether it is official source data, a MedCoder-derived relationship or MedCoder editorial.

Don’t confuse M31.1 with…

MedCoder analysis — pairs from this code’s official notes, distinctions written by MedCoder

The codes most likely to be picked instead of M31.1 — named in its own official notes, or sharing its laterality or encounter family — with what separates them and which documentation moves the case. Each links to the full comparison.

  • M31.9— Specificity relationship (Review)

    Overlapping diagnoses in the same category.

    Overlapping codes in the same category — the documentation decides which is the more specific fit.

    What moves you there: A record that documents no more than “Necrotizing vasculopathy, unspecified” takes M31.9; specificity in the record moves it back here.

    Full comparison: M31.1 vs M31.9 →

Relationships are read from this code's own official notes, its laterality siblings and its encounter family; the wording of each distinction is MedCoder editorial, and the documentation named in each “what moves you there” line is the official note phrase or sibling title itself. Source: CMS ICD-10-CM tabular instructional notes; ICD-10-CM Official Guidelines, Section I.A.12.a.

Code Overview

Thrombotic microangiopathy is a non-billable ICD-10-CM category code (M31.1). A more specific billable subcode must be selected for claims submission.

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

Verify Before Coding

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-derived relationships — computed from published CMS and AHRQ datasets

Other codes that name M31.1 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.

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 category (CCSR)

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

M05.271 — Rheumatoid vasculitis with rheumatoid arthritis of right ankle and foot, 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, M31.10 — Thrombotic microangiopathy, unspecified, 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, +101 more

Contextual Map

Every relationship of M31.1 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 M31.1 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)

Nearest codes (15)

Change history (2)

Deep reference

Published questions and FAQ, every source behind this page with its release and checksum, the date-of-service check and the complete change history.

Common coding questions

MedCoder editorial

Can M31.1 be billed directly?

No. M31.1 (Thrombotic microangiopathy) is a non-billable ICD-10-CM category code. A more specific billable subcode must be selected based on clinical documentation.

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 FY2027 tabular list, index and tables, effective October 1, 2026 Release, file and checksum · Publisher’s page
Claim edits Official source data
CMS Definitions of Medicare Code Edits — v44.0 (October 2026) 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-derived 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 editorial 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.

Current data releases:ICD-10-CM FY2027 · ICD-10-PCS FY2027 · HCPCS October 2026 · MS-DRG v44 · Medicare Code Editor v44.0 · NCCI PTP Q4 2026 · MUE Q4 2026 · NCD code lists 2026-01 · LCD export September 20, 2026 · All releases and sources

Labels on this page: Official source data · MedCoder-derived relationship · MedCoder editorial explanation. How to read the labels · All data sources and release dates · CMS coding rules

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. "M31.1 — Thrombotic microangiopathy." ICD-10-CM FY2027. https://medcoder.ai/icd10/code/m31.1-thrombotic-microangiopathy

Change history

  • FY2022 — October 1, 2021
    Became a non-billable header
    FY2022 changes
  • FY2016 — October 1, 2015
    In the code set at ICD-10-CM adoption
    Thrombotic microangiopathy

Nearest Codes in This Family

Official ICD-10-CM classifications closest to M31.1 in its code family, with their registry titles.

View all codes in the M31 family