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M06.042 ICD-10-CM Code: Rheumatoid arthritis without rheumatoid factor, left hand

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

Coding at a Glance

Risk adjustment
CMS-HCC V28: 1 category · CMS-HCC V22 category 40 · RxHCC V08 category 83

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 v44, 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 93 — Rheumatoid Arthritis and Other Specified Inflammatory Rheumatic Disorders (supersedes HCC 94)

Other models: CMS-HCC V22 HCC 40 · RxHCC V08 HCC 83

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

Coder workflow for M06.042

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

Before you code M06.042

  1. Laterality is coded in this family. Confirm the side documented — right, left, or bilateral — and select the matching code (this page’s code: left). The unspecified-side code applies only when the record states no side. Laterality is assigned from the documented side; where a bilateral code exists and both sides are documented, it is used instead of two unilateral codes (Guidelines I.B.13).

    ReviewM06.041 · right, M06.049 · unspecified

    Guide: Laterality coding →

Choose the right path

  1. Is the side documented?
    Yes → Select the code for the documented side (or the bilateral code when both sides are documented and one exists).
    No → Use the unspecified-side code only when the record states no side; a query is the alternative.

    ReviewM06.041 · right, M06.049 · unspecified

Consider M06.042. 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).
Laterality
Right, left or bilateral as documented; unspecified only when the record states no side (Guidelines I.B.13).
The associated condition or complication
Whether the associated condition the title names is documented; the “with” convention presumes some links, and a provider statement that the conditions are unrelated defeats it (Guidelines I.A.15).

Coding decision scenarios

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

Documentation: The record documents the condition on one side only.

Coding question: Which code in this family applies?

Path: Select the sibling code for the documented side.

Reason: Laterality is assigned from the documented side; the unspecified-side code is for records that state no side (Guidelines I.B.13).

ReviewM06.041 · right, M06.049 · unspecified

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 M06.042 with…

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

The codes most likely to be picked instead of M06.042 — 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.

  • M06.049— 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 “Rheumatoid arthritis without rheumatoid factor, unspecified hand” takes M06.049; specificity in the record moves it back here.

    Full comparison: M06.042 vs M06.049 →

  • M06.041— Laterality relationship (Review)

    Same condition; these differ only in which side is documented.

    The same condition on the other side; the documented side decides, and a bilateral code, where one exists, replaces the pair when both sides are documented.

    What moves you there: A documented right side moves the case to M06.041.

    Full comparison: M06.042 vs M06.041 →

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

Rheumatoid arthritis without rheumatoid factor, left hand is a billable ICD-10-CM diagnosis code (M06.042).

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

  • 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 M06.042 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 Code First instructions: J84.170 — Interstitial lung disease with progressive fibrotic phenotype in diseases classified elsewhere (via M06.-), J84.178 — Other interstitial pulmonary diseases with fibrosis in diseases classified elsewhere (via M06.-).

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 (FY2027)

Potential MS-DRG participation — not a DRG assignment.

FY2027 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 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):MUS003 — Rheumatoid arthritis and related disease (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 condition, opposite side

Same category and title, differing only in which side of the body is affected.

M06.041 — Rheumatoid arthritis without rheumatoid factor, right hand (right)Compare M06.042 vs M06.041 →, M06.049 — Rheumatoid arthritis without rheumatoid factor, unspecified hand (unspecified)Compare M06.042 vs M06.049 →

Same CMS-HCC risk category (V28)

CMS maps these diagnoses to the same Hierarchical Condition Category (Rheumatoid Arthritis and Other Specified Inflammatory Rheumatic Disorders) for risk-adjusted payment.

M06.011 — Rheumatoid arthritis without rheumatoid factor, right shoulder, M06.012 — Rheumatoid arthritis without rheumatoid factor, left shoulder, M06.019 — Rheumatoid arthritis without rheumatoid factor, unspecified shoulder, M06.021 — Rheumatoid arthritis without rheumatoid factor, right elbow, M06.022 — Rheumatoid arthritis without rheumatoid factor, left elbow, M06.029 — Rheumatoid arthritis without rheumatoid factor, unspecified elbow, M06.031 — Rheumatoid arthritis without rheumatoid factor, right wrist, M06.032 — Rheumatoid arthritis without rheumatoid factor, left wrist, M06.039 — Rheumatoid arthritis without rheumatoid factor, unspecified wrist, M06.041 — Rheumatoid arthritis without rheumatoid factor, right hand, M06.049 — Rheumatoid arthritis without rheumatoid factor, unspecified hand, M06.051 — Rheumatoid arthritis without rheumatoid factor, right hip, M06.052 — Rheumatoid arthritis without rheumatoid factor, left hip, M06.059 — Rheumatoid arthritis without rheumatoid factor, unspecified hip, M06.061 — Rheumatoid arthritis without rheumatoid factor, right knee, M06.062 — Rheumatoid arthritis without rheumatoid factor, left knee, M06.069 — Rheumatoid arthritis without rheumatoid factor, unspecified knee, M06.071 — Rheumatoid arthritis without rheumatoid factor, right ankle and foot, M06.072 — Rheumatoid arthritis without rheumatoid factor, left ankle and foot, M06.079 — Rheumatoid arthritis without rheumatoid factor, unspecified ankle and foot, +487 more

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.

Systemic Lupus Erythematosus and Other Specified Systemic Connective Tissue Disorders

Same clinical category (CCSR)

AHRQ's Clinical Classifications Software groups these diagnoses under the same clinical category (Rheumatoid arthritis and related disease).

+340 more

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.

M05.81 — Other rheumatoid arthritis with rheumatoid factor of shoulder (rheumatoid, seropositive, specified NEC, shoulder), M05.82 — Other rheumatoid arthritis with rheumatoid factor of elbow (rheumatoid, seropositive, specified NEC, elbow), M05.83 — Other rheumatoid arthritis with rheumatoid factor of wrist (rheumatoid, seropositive, specified NEC, wrist), M05.84 — Other rheumatoid arthritis with rheumatoid factor of hand (rheumatoid, seropositive, specified NEC, hand joint), M05.85 — Other rheumatoid arthritis with rheumatoid factor of hip (rheumatoid, seropositive, specified NEC, hip), M05.86 — Other rheumatoid arthritis with rheumatoid factor of knee (rheumatoid, seropositive, specified NEC, knee), M05.87 — Other rheumatoid arthritis with rheumatoid factor of ankle and foot (rheumatoid, seropositive, specified NEC, ankle), M05.89 — Other rheumatoid arthritis with rheumatoid factor of multiple sites (rheumatoid, seropositive, specified NEC, multiple sites), M05.8A — Other rheumatoid arthritis with rheumatoid factor of other specified site (rheumatoid, seropositive, specified NEC, specified site NEC), M05.9 — Rheumatoid arthritis with rheumatoid factor, unspecified (rheumatoid, seropositive), M08.00 — Unspecified juvenile rheumatoid arthritis of unspecified site (rheumatoid, juvenile), M08.01 — Unspecified juvenile rheumatoid arthritis, shoulder (rheumatoid, juvenile, shoulder), M08.02 — Unspecified juvenile rheumatoid arthritis of elbow (rheumatoid, juvenile, elbow), M08.03 — Unspecified juvenile rheumatoid arthritis, wrist (rheumatoid, juvenile, wrist), M08.04 — Unspecified juvenile rheumatoid arthritis, hand (rheumatoid, juvenile, hand joint), M08.05 — Unspecified juvenile rheumatoid arthritis, hip (rheumatoid, juvenile, hip), M08.06 — Unspecified juvenile rheumatoid arthritis, knee (rheumatoid, juvenile, knee), M08.07 — Unspecified juvenile rheumatoid arthritis, ankle and foot (rheumatoid, juvenile, ankle), M08.08 — Unspecified juvenile rheumatoid arthritis, vertebrae (rheumatoid, juvenile, vertebra), M08.09 — Unspecified juvenile rheumatoid arthritis, multiple sites (rheumatoid, juvenile, multiple site), +172 more

Contextual Map

Every relationship of M06.042 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 M06.042 with these 2 related codes in Claim Check

Hierarchy

Referenced by Code First instructions

Clinical classification (CCSR)

Risk adjustment (CMS-HCC)

  • HCC 93 — Rheumatoid Arthritis and Other Specified Inflammatory Rheumatic Disorders [CMS-HCC]: “Rheumatoid Arthritis and Other Specified Inflammatory Rheumatic Disorders — supersedes HCC 94 (Systemic Lupus Erythematosus and Other Specified Systemic Connective Tissue Disorders)”— 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. 18,439 same-MDC procedures group here; browse them on the MDC page.”— CMS MS-DRG Definitions Manual · FY2027

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

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.

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
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 — v44 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.

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 structured relationship · MedCoder 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. "M06.042 — Rheumatoid arthritis without rheumatoid factor, left hand." ICD-10-CM FY2027. https://medcoder.ai/icd10/code/m06.042-rheumatoid-arthritis-without-rheumatoid-factor-left-hand

Change history

  • FY2016 — October 1, 2015
    In the code set at ICD-10-CM adoption
    Rheumatoid arthritis without rheumatoid factor, left hand

No changes since FY2016 — additions, deletions, description changes and billable-status changes are tracked through FY2027, 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 M06.042 in its code family, with their registry titles.

View all codes in the M06 family