ICD-10-CM 2027 diagnosis code
G44.1Vascular headache, not elsewhere classified
G44.1 is a valid, billable ICD-10-CM code for vascular headache, not elsewhere classified. It can be reported on claims for dates of service from October 1, 2026 – September 30, 2027.
Code unchanged since ICD-10-CM took effect on October 1, 2015. Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data
About G44.1
G44.1 is the ICD-10-CM diagnosis code for vascular headache, not elsewhere classified. It belongs to category G44 (other headache syndromes), block G40-G47 (episodic and paroxysmal disorders) and chapter 6 (diseases of the nervous system). It is billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.
Within G44 (other headache syndromes), G44.1 is specifically for vascular headache, not elsewhere classified. Related codes cover cluster headaches and other trigeminal autonomic cephalgias (TAC) (G44.0), tension-type headache (G44.2), post-traumatic headache (G44.3), drug-induced headache, not elsewhere classified (G44.4), complicated headache syndromes (G44.5) and other specified headache syndromes (G44.8).
The conditions in its Excludes2 note aren't part of G44.1, but may be coded alongside it if the patient has both: cluster headache (G44.0), complicated headache syndromes (G44.5-), drug-induced headache (G44.4-), migraine (G43.-) and 3 more.
It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.
In MS-DRG v44.0, it is part of the grouping logic for DRG 102 (Headaches with MCC, relative weight 1.1201) and DRG 103 (Headaches without MCC, relative weight 0.822), in MDC 01 (Diseases and Disorders of the Nervous System), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.
It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.
Before ICD-10, this condition was coded in ICD-9-CM as 784.0 (headache).
Coding notes
Notes that apply from higher levels
Instructions written at a parent level also apply to G44.1.
› From G44 Other headache syndromes
Broader instructions also apply from Chapter 6: Diseases of the nervous system.
Alphabetic index entries
1 entriesTerms in the official ICD-10-CM index that lead to G44.1.
MS-DRG v44.0 grouping
All DRGs →Inpatient MS-DRGs this diagnosis can group to, as the principal or a secondary diagnosis, depending on the rest of the claim.
MDC 01 · Diseases and Disorders of the Nervous System
ICD-9-CM equivalent
Converter →- 784.0Headacheapproximate
From the CMS 2018 General Equivalence Mappings (GEMs), the final GEMs release.
Code history
- 2016
- 2017
- 2018
- 2019
- 2020
- 2021
- 2022
- 2023
- 2024
- 2025
- 2026
- 2027
- FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
- No changes since FY2016.
Common questions about G44.1
Is G44.1 billable?
- Yes. G44.1 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can G44.1 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict G44.1 as a principal diagnosis.
Is G44.1 a CC or MCC?
- No. G44.1 is neither a CC nor an MCC under MS-DRG v44.0.
What DRG does G44.1 group to?
- G44.1 is used in the MS-DRG v44.0 logic for MS-DRG 102 (Headaches with MCC) and MS-DRG 103 (Headaches without MCC). Which one applies depends on whether it is the principal diagnosis and on the rest of the claim.
What is the ICD-9 code for G44.1?
- The CMS General Equivalence Mappings map G44.1 to ICD-9-CM 784.0.