Skip to main content

M04.1 ICD-10-CM Code: Periodic fever syndromes

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

Coding at a Glance

Tabular directives
4 inclusion terms · 1 Excludes2
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 94 — Systemic Lupus Erythematosus and Other Specified Systemic Connective Tissue Disorders

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.

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for M04.1 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 M04.1 itself; “inherited from” names the category or block whose note applies here.

Inclusion Terms

Alternative terms the tabular list files under this code.

  • Familial Mediterranean fever
  • Hyperimmunoglobin D syndrome
  • Mevalonate kinase deficiency
  • Tumor necrosis factor receptor associated periodic syndrome [TRAPS]

Excludes2 — Not Included Here

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

Source: inherited from M04

Coder workflow for M04.1

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 M04.1(1 note)

    Coding workflow: The conditions named in this note are not included in M04.1. When the record documents both, both may be reported; the note is a boundary, not a prohibition.

    CompareK50

    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.

Don’t confuse M04.1 with…

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

The codes most likely to be picked instead of M04.1 — 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.

  • M04.9— 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 “Autoinflammatory syndrome, unspecified” takes M04.9; specificity in the record moves it back here.

    Full comparison: M04.1 vs M04.9 →

  • K50— Excludes2 relationship (Informational)

    Distinct conditions — both may be reported.

    A distinct condition — both may be reported when both are documented.

    What moves you there: Documentation of Crohn's disease adds K50; it is not part of this code and both may be reported when both are documented.

    Full comparison: M04.1 vs K50 →

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

Periodic fever syndromes is a billable ICD-10-CM diagnosis code (M04.1).

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 (9)

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

  • 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 M04.1 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 Code Also instruction: E85.0 — Non-neuropathic heredofamilial amyloidosis (via M04.-).

These codes suggest coding this condition alongside when both are present.

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):MUS036 — Autoinflammatory syndromes (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 CMS-HCC risk category (V28)

CMS maps these diagnoses to the same Hierarchical Condition Category (Systemic Lupus Erythematosus and Other Specified Systemic Connective Tissue Disorders) for risk-adjusted payment.

M02.352 — Reiter's disease, left hip, M02.359 — Reiter's disease, unspecified hip, M02.361 — Reiter's disease, right knee, M02.362 — Reiter's disease, left knee, M02.369 — Reiter's disease, unspecified knee, M02.371 — Reiter's disease, right ankle and foot, M02.372 — Reiter's disease, left ankle and foot, M02.379 — Reiter's disease, unspecified ankle and foot, M02.38 — Reiter's disease, vertebrae, M02.39 — Reiter's disease, multiple sites, M04.2 — Cryopyrin-associated periodic syndromes, M04.8 — Other autoinflammatory syndromes, M04.9 — Autoinflammatory syndrome, unspecified, M06.4 — Inflammatory polyarthropathy, M12.00 — Chronic postrheumatic arthropathy [Jaccoud], unspecified site, M12.011 — Chronic postrheumatic arthropathy [Jaccoud], right shoulder, M12.012 — Chronic postrheumatic arthropathy [Jaccoud], left shoulder, M12.019 — Chronic postrheumatic arthropathy [Jaccoud], unspecified shoulder, M12.021 — Chronic postrheumatic arthropathy [Jaccoud], right elbow, M12.022 — Chronic postrheumatic arthropathy [Jaccoud], left elbow, +50 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.

Rheumatoid Arthritis and Other Specified Inflammatory Rheumatic Disorders

Same clinical category (CCSR)

AHRQ's Clinical Classifications Software groups these diagnoses under the same clinical category (Autoinflammatory syndromes).

M04.2 — Cryopyrin-associated periodic syndromes, M04.8 — Other autoinflammatory syndromes, M04.9 — Autoinflammatory syndrome, unspecified

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.

M00.81 — Arthritis due to other bacteria, shoulder (pyogenic or pyemic, bacterial NEC, shoulder), M00.82 — Arthritis due to other bacteria, elbow (pyogenic or pyemic, bacterial NEC, elbow), M00.83 — Arthritis due to other bacteria, wrist (pyogenic or pyemic, bacterial NEC, wrist), M00.84 — Arthritis due to other bacteria, hand (pyogenic or pyemic, bacterial NEC, hand joint), M00.85 — Arthritis due to other bacteria, hip (pyogenic or pyemic, bacterial NEC, hip), M00.86 — Arthritis due to other bacteria, knee (pyogenic or pyemic, bacterial NEC, knee), M00.87 — Arthritis due to other bacteria, ankle and foot (pyogenic or pyemic, bacterial NEC, ankle), M00.88 — Arthritis due to other bacteria, vertebrae (pyogenic or pyemic, bacterial NEC, vertebra), M00.89 — Polyarthritis due to other bacteria (pyogenic or pyemic, bacterial NEC, multiple site), M00.9 — Pyogenic arthritis, unspecified (pyogenic or pyemic), M05.70 — Rheumatoid arthritis with rheumatoid factor of unspecified site without organ or systems involvement (rheumatoid, seropositive, without organ involvement), M05.71 — Rheumatoid arthritis with rheumatoid factor of shoulder without organ or systems involvement (rheumatoid, seropositive, without organ involvement, shoulder), M05.72 — Rheumatoid arthritis with rheumatoid factor of elbow without organ or systems involvement (rheumatoid, seropositive, without organ involvement, elbow), M05.73 — Rheumatoid arthritis with rheumatoid factor of wrist without organ or systems involvement (rheumatoid, seropositive, without organ involvement, wrist), M05.74 — Rheumatoid arthritis with rheumatoid factor of hand without organ or systems involvement (rheumatoid, seropositive, without organ involvement, hand joint), M05.75 — Rheumatoid arthritis with rheumatoid factor of hip without organ or systems involvement (rheumatoid, seropositive, without organ involvement, hip), M05.76 — Rheumatoid arthritis with rheumatoid factor of knee without organ or systems involvement (rheumatoid, seropositive, without organ involvement, knee), M05.77 — Rheumatoid arthritis with rheumatoid factor of ankle and foot without organ or systems involvement (rheumatoid, seropositive, without organ involvement, ankle), M05.79 — Rheumatoid arthritis with rheumatoid factor of multiple sites without organ or systems involvement (rheumatoid, seropositive, without organ involvement, multiple sites), M05.7A — Rheumatoid arthritis with rheumatoid factor of other specified site without organ or systems involvement (rheumatoid, seropositive, without organ involvement, specified site NEC), +506 more

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.

Blood Glucose Test, Gamma-glutamyl Transferase (GGT) Test, Hepatitis Testing, HIV Screening Test, Thyroid Stimulating Hormone (TSH)

Contextual Map

Every relationship of M04.1 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 M04.1 with this related code in Claim Check

Hierarchy

Referenced by Code Also instructions

Clinical classification (CCSR)

Risk adjustment (CMS-HCC)

  • HCC 94 — Systemic Lupus Erythematosus and Other Specified Systemic Connective Tissue Disorders [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. 18,439 same-MDC procedures group here; browse them on the MDC page.”— CMS MS-DRG Definitions Manual · FY2027

Index entries (9)

  • Arthritis, arthritic (acute) (chronic) (nonpyogenic) (subacute), in (due to), Mediterranean fever, familial[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Deficiency, deficient, mevalonate kinase[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Fever (inanition) (of unknown origin) (persistent) (with chills) (with rigor), Mediterranean, familial[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Fever (inanition) (of unknown origin) (persistent) (with chills) (with rigor), periodic (Mediterranean)[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Mediterranean, fever, familial[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Syndrome, hyperimmunoglobulin D[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Syndrome, periodic fever[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Syndrome, tumor necrosis factor receptor associated periodic (TRAPS)[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • and 1 more

Nearest codes

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.

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. "M04.1 — Periodic fever syndromes." ICD-10-CM FY2027. https://medcoder.ai/icd10/code/m04.1-periodic-fever-syndromes

Change history

  • FY2017 — October 1, 2016
    Added to the code set
    Periodic fever syndromes
    FY2017 changes

Nearest Codes in This Family

Official ICD-10-CM classifications closest to M04.1 in its code family, with their registry titles.

View all codes in the M04 family