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G44.1 ICD-10-CM Code: Vascular headache, not elsewhere classified

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

Coding at a Glance

Tabular directives
1 Excludes1 · 11 Excludes2

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.

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.

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for G44.1 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 G44.1 itself; “inherited from” names the category or block whose note applies here.

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).

Source: inherited from G44

Excludes2 — Not Included Here

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

Coder workflow for G44.1

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

Before you code G44.1

  1. “Other” (NEC) means the condition is specified in the record but no dedicated code captures it. Confirm the documented form is not one a sibling code names before settling on G44.1; if the record states no specifics at all, the unspecified sibling applies instead. “Other” codes are for documented conditions the classification gives no specific code; “unspecified” codes are for records lacking the detail (Guidelines I.A.9.a, I.A.9.b).

    ReviewG44.2, G44.3

    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 G44.1. 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 a condition named in G44.1’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.

    ReviewR51.9

Consider G44.1. 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).
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 G44.1(1 note)

    Coding workflow: If the documentation supports a condition named in this note, do not simply proceed with G44.1: the two are not reported together. The one exception is when the record shows the two conditions are unrelated to each other.

    CompareR51.9

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

  • Excludes2 — not part of G44.1(11 notes)

    Coding workflow: The conditions named in this note are not included in G44.1. When the record documents both, both may be reported; the note is a boundary, not a prohibition.

    CompareG44.0, G44.5, G44.4, G43, G44.8, G44.3

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

Coding decision scenarios

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

Documentation: Both the condition G44.1 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).

ReviewR51.9

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 G44.1 with…

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

The codes most likely to be picked instead of G44.1 — 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.

  • R51.9— Excludes1 conflict (Excludes1 — generally not reported together)

    Not coded here — the tabular list excludes this pair for the same encounter.

    Not reported together with this code, except where the two conditions are documented as unrelated.

    What moves you there: Documentation of headache NOS moves the case to R51.9; the two are not reported together unless documented as unrelated.

    Full comparison: G44.1 vs R51.9 →

  • G44.0— 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 cluster headache adds G44.0; it is not part of this code and both may be reported when both are documented.

    Full comparison: G44.1 vs G44.0 →

  • G44.5— 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 complicated headache syndromes adds G44.5; it is not part of this code and both may be reported when both are documented.

    Full comparison: G44.1 vs G44.5 →

  • G44.4— 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 drug-induced headache adds G44.4; it is not part of this code and both may be reported when both are documented.

    Full comparison: G44.1 vs G44.4 →

  • G43— 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 migraine adds G43; it is not part of this code and both may be reported when both are documented.

    Full comparison: G44.1 vs G43 →

  • G44.8— 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 other specified headache syndromes adds G44.8; it is not part of this code and both may be reported when both are documented.

    Full comparison: G44.1 vs G44.8 →

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

Vascular headache, not elsewhere classified is a billable ICD-10-CM diagnosis code (G44.1).

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 (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

  • 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 G44.1 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 3 Excludes2 notes across 2 chapters: G43 — Migraine (via G44.-), G89 — Pain, not elsewhere classified (via G44.-), R51 — Headache (via G44.-).

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

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 2 MS-DRGs: DRG 102 (MDC 01), DRG 103 (MDC 01).

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

Clinical classification (AHRQ CCSR):NVS010 — Headache; including migraine (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 (Headache; including migraine).

G44.021 — Chronic cluster headache, intractable, G44.029 — Chronic cluster headache, not intractable, G44.031 — Episodic paroxysmal hemicrania, intractable, G44.039 — Episodic paroxysmal hemicrania, not intractable, G44.041 — Chronic paroxysmal hemicrania, intractable, G44.049 — Chronic paroxysmal hemicrania, not intractable, G44.051 — Short lasting unilateral neuralgiform headache with conjunctival injection and tearing (SUNCT), intractable, G44.059 — Short lasting unilateral neuralgiform headache with conjunctival injection and tearing (SUNCT), not intractable, G44.091 — Other trigeminal autonomic cephalgias (TAC), intractable, G44.099 — Other trigeminal autonomic cephalgias (TAC), not intractable, G44.201 — Tension-type headache, unspecified, intractable, G44.209 — Tension-type headache, unspecified, not intractable, G44.211 — Episodic tension-type headache, intractable, G44.219 — Episodic tension-type headache, not intractable, G44.221 — Chronic tension-type headache, intractable, G44.229 — Chronic tension-type headache, not intractable, G44.301 — Post-traumatic headache, unspecified, intractable, G44.309 — Post-traumatic headache, unspecified, not intractable, G44.311 — Acute post-traumatic headache, intractable, G44.319 — Acute post-traumatic headache, not intractable, +70 more

Same Index main term, other category

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

G43.909 — Migraine, unspecified, not intractable, without status migrainosus (migraine), G43.C0 — Periodic headache syndromes in child or adult, not intractable (periodic syndromes in adults and children), G43.C1 — Periodic headache syndromes in child or adult, intractable (periodic syndromes in adults and children, intractable), G97.1 — Other reaction to spinal and lumbar puncture (lumbar puncture), O29.4 — Spinal and epidural anesthesia induced headache during pregnancy (spinal and epidural anesthesia - induced, in pregnancy), O74.5 — Spinal and epidural anesthesia-induced headache during labor and delivery (spinal and epidural anesthesia - induced, in labor and delivery), O89.4 — Spinal and epidural anesthesia-induced headache during the puerperium (spinal and epidural anesthesia - induced, postpartum, puerperal), R51.0 — Headache with orthostatic component, not elsewhere classified (with, positional component NEC), R51.9 — Headache, unspecified, T88.59 — Other complications of anesthesia (spinal and epidural anesthesia - induced)

Contextual Map

Every relationship of G44.1 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 G44.1 with these 9 related codes in Claim Check

Hierarchy

Excludes2

Referenced by Excludes2 notes

  • G43 — Migraine[Excludes2](via G44.-): “headache syndromes (G44.-)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
  • G89 — Pain, not elsewhere classified[Excludes2](via G44.-): “headache syndromes (G44.-)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
  • R51 — Headache[Excludes2](via G44.-): “migraine and other headache syndromes (G43-G44)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026

Clinical classification (CCSR)

MS-DRG Grouper

MDC crossing

  • MDC 01 — Diseases and Disorders of the Nervous System[MDC crossing]: “Diseases and Disorders of the Nervous System — 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. 8,919 same-MDC procedures group here; browse them on the MDC page.”— CMS MS-DRG Definitions Manual · FY2027

Index entries

  • Headache, vascular NEC[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026

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

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
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. "G44.1 — Vascular headache, not elsewhere classified." ICD-10-CM FY2027. https://medcoder.ai/icd10/code/g44.1-vascular-headache-not-elsewhere-classified

Change history

  • FY2016 — October 1, 2015
    In the code set at ICD-10-CM adoption
    Vascular headache, not elsewhere classified

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 G44.1 in its code family, with their registry titles.

View all codes in the G44 family